Reviews from Amazon

Reviews elsewhere on the web:

Mark Buchanan

Nexus: Small Worlds and the Groundbreaking Theory of Networks

The version I read was entitled Small World: uncovering nature's hidden networks.

You've probably heard that no-one is more than six handshakes away fromt the President of the USA, due to what is known as the small-world effect. In Small Worlds Mark Buchanan illustrates this effect with plenty of examples. In an easy to read book he shows how the connections in typical networks makes such an effect pretty much inevitable, and he goes on to look at some of the consequences of this effect - how systems often have a 'tipping point'. If you want to find out about the small world effect, I would say that this book is an excellent place to start.

The book doesn't just deal with social networks, but with many examples of the small world effect. There are chapters on the workings of the brain, the internet, and the spread of disease. Buchanan also looks at the connections of ecological systems and the role of networks in economics - why the rich get richer. Indeed my one complaint about the book is that it tries to relate too much to the small world effect. By being so wide ranging, it seems to move away from a theory with specific predictions towards one which can explain anything (and so may well end up explaining nothing)

Amazon.com info

Paperback 238 pages
ISBN: 0393324427
Salesrank: 29109
Weight:0.45 lbs

Published: 2003 W. W. Norton & Company

Amazon price $10.85

Marketplace:New from $9.52:Used from $6.46

Buy from Amazon.com

Amazon.co.uk info

Paperback 238 pages
ISBN: 0393324427
Salesrank: 68850
Weight:0.45 lbs

Published: 2003 W. W. Norton & Co.

Amazon price £9.49

Marketplace:New from £3.74:Used from £3.90

Buy from Amazon.co.uk

Amazon.ca info

Paperback 238 pages
ISBN: 0393324427
Salesrank: 52889
Weight:0.45 lbs

Published: 2003 WW Norton

Amazon price CDN$ 13.87

Marketplace:New from CDN$ 7.36:Used from CDN$ 25.79

Buy from Amazon.ca

Book Description
As Chaos explained the science of disorder, Nexus reveals the new science of connection and the odd logic of six degrees of separation. "If you ever wanted to know how many links connect you and the Pope, or why when the U.S. Federal Reserve Bank sneezes the global economy catches cold, read this book," writes John L. Casti (Santa Fe Institute). This "cogent and engaging" (Nature) work presents the fundamental principles of the emerging field of "small-worlds" theory—the idea that a hidden pattern is the key to how networks interact and exchange information, whether that network is the information highway or the firing of neurons in the brain. Mathematicians, physicists, computer scientists, and social scientists are working to decipher this complex organizational system, for it may yield a blueprint of dynamic interactions within our physical as well as social worlds. Highlighting groundbreaking research behind network theory, "Mark Buchanan's graceful, lucid, nontechnical and entertaining prose" (Mark Granovetter) documents the mounting support among various disciplines for the small-worlds idea and demonstrates its practical applications to diverse problems—from the volatile global economy or the Human Genome Project to the spread of infectious disease or ecological damage. Nexus is an exciting introduction to the hidden geometry that weaves our lives so inextricably together.

Book Description

As Chaos explained the science of disorder, Nexus reveals the new science of connection and the odd logic of six degrees of separation.

"If you ever wanted to know how many links connect you and the Pope, or why when the U.S. Federal Reserve Bank sneezes the global economy catches cold, read this book," writes John L. Casti (Santa Fe Institute). This "cogent and engaging" (Nature) work presents the fundamental principles of the emerging field of "small-worlds" theory—the idea that a hidden pattern is the key to how networks interact and exchange information, whether that network is the information highway or the firing of neurons in the brain. Mathematicians, physicists, computer scientists, and social scientists are working to decipher this complex organizational system, for it may yield a blueprint of dynamic interactions within our physical as well as social worlds.

Highlighting groundbreaking research behind network theory, "Mark Buchanan's graceful, lucid, nontechnical and entertaining prose" (Mark Granovetter) documents the mounting support among various disciplines for the small-worlds idea and demonstrates its practical applications to diverse problems—from the volatile global economy or the Human Genome Project to the spread of infectious disease or ecological damage. Nexus is an exciting introduction to the hidden geometry that weaves our lives so inextricably together.

Good High-Level Overview ****
Nexus is a book that delves into network theory, specifically the implications of so-called "small-world" networks. Small-world networks are signified by low degrees of separation and clustering, yielding the "six-degrees" phenomena that connects a person to Kevin Bacon (or anyone else) within approximately six links, all the while most connections are maintained amongst close groups of friends or colleagues. Research into small-world networks is a new and rapidly advancing field of complexity theory. Written in 2002, Nexus outlines the impact of small-world networks on many topics, including biology, ecology, economics, and technology. However, the cutting-edge nature of the field, combined with the now somewhat dated year of publication, limits the scope of the book. In my opinion, while the book was interesting as a high-level overview, it lacked the level of detail that I would have preferred. While I have not yet read Linked or Six Degrees, I'm hoping that those books dive into the topic a bit further.

Good High-Level Overview ****

Nexus is a book that delves into network theory, specifically the implications of so-called "small-world" networks. Small-world networks are signified by low degrees of separation and clustering, yielding the "six-degrees" phenomena that connects a person to Kevin Bacon (or anyone else) within approximately six links, all the while most connections are maintained amongst close groups of friends or colleagues.

Research into small-world networks is a new and rapidly advancing field of complexity theory. Written in 2002, Nexus outlines the impact of small-world networks on many topics, including biology, ecology, economics, and technology. However, the cutting-edge nature of the field, combined with the now somewhat dated year of publication, limits the scope of the book.

In my opinion, while the book was interesting as a high-level overview, it lacked the level of detail that I would have preferred. While I have not yet read Linked or Six Degrees, I'm hoping that those books dive into the topic a bit further.

Very interesting! *****
A really interesting book. It's not hard to read and open your eyes on a new approach in understanding how real things go.

Very interesting! *****

A really interesting book. It's not hard to read and open your eyes on a new approach in understanding how real things go.

I liked "Linked: How Everything is Connected" better ***
I am neither a scientist nor an economist. I wanted to learn more about this emerging science of networks. I bought this and "Linked: How Everything Is Connected to Everything Else and What It Means". I found "Linked" to be the better of the two books. It was entertaining and easy to read, and had a lot of interesting examples that were very easy to understand. I think most people looking for a non-academic treatment would find it interesting.

I liked "Linked: How Everything is Connected" better ***

I am neither a scientist nor an economist. I wanted to learn more about this emerging science of networks. I bought this and "Linked: How Everything Is Connected to Everything Else and What It Means". I found "Linked" to be the better of the two books. It was entertaining and easy to read, and had a lot of interesting examples that were very easy to understand. I think most people looking for a non-academic treatment would find it interesting.

The science behind Six Degrees of Separation *****
Buchanan, former editor of Nature and the New Scientist, is an engaging writer with a background in physics. He uses his strong storytelling ability to weave stories of what might otherwise be considered rather tedious research projects into a compelling journey through the ideas behind the Six Degrees of Separation concept. Covering everything from research into why fireflies synchronize into a single flashing mass to how the rich get richer, Nexus explains the Small World networks theory in a way that is fascinating and easily mapped onto what you may already suspect about how the world works. Buchanan's descriptions of how the Internet and the AIDS virus have grown are outstanding. The book gives you the language and tools you need to confirm that the world really is very, very small.

The science behind Six Degrees of Separation *****

Buchanan, former editor of Nature and the New Scientist, is an engaging writer with a background in physics. He uses his strong storytelling ability to weave stories of what might otherwise be considered rather tedious research projects into a compelling journey through the ideas behind the Six Degrees of Separation concept. Covering everything from research into why fireflies synchronize into a single flashing mass to how the rich get richer, Nexus explains the Small World networks theory in a way that is fascinating and easily mapped onto what you may already suspect about how the world works. Buchanan's descriptions of how the Internet and the AIDS virus have grown are outstanding. The book gives you the language and tools you need to confirm that the world really is very, very small.

A new science ****
The 20th century witnessed the birth of several entirely new branches of science. Some of the more popular include relativity, nuclear physics, genetics, and solid state science. But there is one field that connects them all, the science of networks, whether it is networks of humans in a city, animals in an environment, water molecules in a lake or computers on the web. This book provides a ground-up introduction to networks, a history of the ideas, and how they are manifested in everything we do. The author explains how various phenomena are explained using networks, such as the spread of diseases, the movement of stock prices, and of course, business networking. This book is just one of a whole wave of books published in the past 20 years on this subject; but is better than most in that it approaches the topic on scientific principles. I recommend this book.

A new science ****

The 20th century witnessed the birth of several entirely new branches of science. Some of the more popular include relativity, nuclear physics, genetics, and solid state science. But there is one field that connects them all, the science of networks, whether it is networks of humans in a city, animals in an environment, water molecules in a lake or computers on the web. This book provides a ground-up introduction to networks, a history of the ideas, and how they are manifested in everything we do. The author explains how various phenomena are explained using networks, such as the spread of diseases, the movement of stock prices, and of course, business networking. This book is just one of a whole wave of books published in the past 20 years on this subject; but is better than most in that it approaches the topic on scientific principles. I recommend this book.

My world just got smaller ***
Mark Buchanan does an excellent job of explaining the Small World phenomenon in this readable and well balanced account of modern network theory. He begins by explaining Stanley Milgram's social network experiment of the sixties which revelaed that there are rarely more than six steps between any two people on the planet - now known as the principle of six degrees of separation. He then goes on to explain the clustering tendency of connections in our social networks, in the web and in nature. Loose connections step from one cluster to the next and highly connected people become the aristocrats of complex networks. Add in the economic principle of the rich getting richer, apply Pareto's 80:20 rule and the next thing you know you are heading for possible solutions to the world AIDS epidemic. I found the ideas in this book utterly convincing and finished it optimistic and excited about the possibilities of this new area of understanding.

My world just got smaller ***

Mark Buchanan does an excellent job of explaining the Small World phenomenon in this readable and well balanced account of modern network theory.

He begins by explaining Stanley Milgram's social network experiment of the sixties which revelaed that there are rarely more than six steps between any two people on the planet - now known as the principle of six degrees of separation. He then goes on to explain the clustering tendency of connections in our social networks, in the web and in nature.

Loose connections step from one cluster to the next and highly connected people become the aristocrats of complex networks. Add in the economic principle of the rich getting richer, apply Pareto's 80:20 rule and the next thing you know you are heading for possible solutions to the world AIDS epidemic.

I found the ideas in this book utterly convincing and finished it optimistic and excited about the possibilities of this new area of understanding.

Good introduction to a broad subject *****
The author makes a strong case that many diverse phenomena can be modelled in very similar ways. This book can be summarized as a very brief introduction to network models, followed by numerous examples from the real world. The level of mathematical sophistication needed to comprehend the matterial is minimal. I do not believe there are any equations in the entire book. There are many easily understood graphs and a few percentages. The basic concept of the networks is very easy to explain and to understand. The applications are the interesting part. Thoughout the pages are clear and interesting examples that make you want to turn the page to see what is coming next. In my case I often found myself thinking how I would have approached the problem and more importantly what problems could this have been applied to. Any book that can do that is a good one in my book! Like many good books, this one leaves more questions unanswered than it answers. The subject area is a generic one that allows it's self to be applied in many many different fields. The question becomes not is this model of the world valid but rather how can it be applied. This was a quick read, certain to change my views on how the world works.

Good introduction to a broad subject *****

The author makes a strong case that many diverse phenomena can be modelled in very similar ways. This book can be summarized as a very brief introduction to network models, followed by numerous examples from the real world.

The level of mathematical sophistication needed to comprehend the matterial is minimal. I do not believe there are any equations in the entire book. There are many easily understood graphs and a few percentages.

The basic concept of the networks is very easy to explain and to understand. The applications are the interesting part. Thoughout the pages are clear and interesting examples that make you want to turn the page to see what is coming next. In my case I often found myself thinking how I would have approached the problem and more importantly what problems could this have been applied to. Any book that can do that is a good one in my book!

Like many good books, this one leaves more questions unanswered than it answers. The subject area is a generic one that allows it's self to be applied in many many different fields. The question becomes not is this model of the world valid but rather how can it be applied.

This was a quick read, certain to change my views on how the world works.

It's a small world after all. *****
I just finished reading Nexus right after I finished Steven Johnson's book, Emergence. Both are great, quick reads. The ideas are fascinating and build upon chaos theory that James Gleick gives a history of in Chaos, which is the last book I read that addressed topics such as complexity. It's a great thrill to receive journalistic reports on what has happened in the small-worlds theory and gaining a cursory understanding of its current and future applications. I also just started reading Harold Morowitz's The Emergence of Everything, which is interesting in its subject matter while the writing is much more austere than in Emergence and Nexus. I look forward to reading everything I can on the small-worlds, complexity theory-type popular science books.

It's a small world after all. *****

I just finished reading Nexus right after I finished Steven Johnson's book, Emergence. Both are great, quick reads. The ideas are fascinating and build upon chaos theory that James Gleick gives a history of in Chaos, which is the last book I read that addressed topics such as complexity. It's a great thrill to receive journalistic reports on what has happened in the small-worlds theory and gaining a cursory understanding of its current and future applications. I also just started reading Harold Morowitz's The Emergence of Everything, which is interesting in its subject matter while the writing is much more austere than in Emergence and Nexus. I look forward to reading everything I can on the small-worlds, complexity theory-type popular science books.

Networks of sex partners and the Net-Are they really related *****
The surprising answer is yes. I picked this book up after reading Steven Strogatz's Sync which mentions a great deal about the science of networks. Buchanan explains how networks exist everywhere - the net, the web, the power grid, our circle of friends, our sex partners - and that they are in fact very similar to one another. The phrase "six degrees of separation" comes from the fact that two randomly chosen people, A and B, will on average be connected by six social links. A knows C who knows D who knows E who knows F who knows G who finally knows B. Considering the world has over 6 billion people, an average separation of 6 seems unbelievable small, but the explanation of this incredible phenomenon lies in the makeup of our social network. Our close friends know each other but our cluster of friends has weak ties to other clusters through acquaintances, people we really don't know that well - that's why when one is looking for a job, it's better to tell an acquaintance rather than a friend so that our inquiry can jump to other clusters. Our social network is essentially highly clustered but enough links exist between these clusters to allow us to jump from ourselves to any other person through just an average of six links. Buchanan shows us how this kind of network exists everywhere as mentioned above although he distinguishes between egalitarian networks where clusters are roughly the same size and aristocratic networks such as the WWW where gigantic hubs like Amazon.com exist that link to millions of websites. One of the most interesting chapters in the book deals with sexual networks. It turns out that in the network of sex partners, certain people have a great many more links than the average person in the network. Buchanan explains how the structure of the sexual network actually accounts for the rapid spread of HIV. The virus spread quickly because the hubs in the network spread it to their numerous partners. In fact, it turns out that a significant percentage of the inital HIV cases had a sexual relationship with one particular flight attendant. As I wrote in my review for Strogatz's Sync, we are entering an era of science where disparate fields of study are being linked because many phenomena that we used to regard as unrelated now appear to have very similar underlying bases. It is exciting to read books like Nexus because it illustrates this point. You should definitely read this book if your are interested in the science of networks and want to know how so many different phenomena are being explained by the same underlying principles.

Networks of sex partners and the Net-Are they really related *****

The surprising answer is yes. I picked this book up after reading Steven Strogatz's Sync which mentions a great deal about the science of networks. Buchanan explains how networks exist everywhere - the net, the web, the power grid, our circle of friends, our sex partners - and that they are in fact very similar to one another.

The phrase "six degrees of separation" comes from the fact that two randomly chosen people, A and B, will on average be connected by six social links. A knows C who knows D who knows E who knows F who knows G who finally knows B. Considering the world has over 6 billion people, an average separation of 6 seems unbelievable small, but the explanation of this incredible phenomenon lies in the makeup of our social network. Our close friends know each other but our cluster of friends has weak ties to other clusters through acquaintances, people we really don't know that well - that's why when one is looking for a job, it's better to tell an acquaintance rather than a friend so that our inquiry can jump to other clusters. Our social network is essentially highly clustered but enough links exist between these clusters to allow us to jump from ourselves to any other person through just an average of six links. Buchanan shows us how this kind of network exists everywhere as mentioned above although he distinguishes between egalitarian networks where clusters are roughly the same size and aristocratic networks such as the WWW where gigantic hubs like Amazon.com exist that link to millions of websites.

One of the most interesting chapters in the book deals with sexual networks. It turns out that in the network of sex partners, certain people have a great many more links than the average person in the network. Buchanan explains how the structure of the sexual network actually accounts for the rapid spread of HIV. The virus spread quickly because the hubs in the network spread it to their numerous partners. In fact, it turns out that a significant percentage of the inital HIV cases had a sexual relationship with one particular flight attendant.

As I wrote in my review for Strogatz's Sync, we are entering an era of science where disparate fields of study are being linked because many phenomena that we used to regard as unrelated now appear to have very similar underlying bases. It is exciting to read books like Nexus because it illustrates this point. You should definitely read this book if your are interested in the science of networks and want to know how so many different phenomena are being explained by the same underlying principles.

Complete and good to read. ****
In this book, Buchanan introduces to the non-expert audience one of the most recent and stimulating theories in the study of complexity: the theory of networks. The author does so by using a clear and fresh prose, deprived of specialistic mathematical terms. He will guide the reader through this theory and its many practical applications, being they in economy, epidemiology or ecology. The book is not exactly linear, somewhat jumping from one example to another and a few digressions are almost confusing. It is rich in information and very good references, although a couple of imprecisions about Euclid and Pythagoras had me frowning. However, being not too long, this book manages to get the reader to understand the points made and never ceased to surprise and interest me. I recommend this book to the non-mathematician interested in complexity and theory of networks. The book will be an ideal starting point for further reading.

Complete and good to read. ****

In this book, Buchanan introduces to the non-expert audience one of the most recent and stimulating theories in the study of complexity: the theory of networks. The author does so by using a clear and fresh prose, deprived of specialistic mathematical terms. He will guide the reader through this theory and its many practical applications, being they in economy, epidemiology or ecology. The book is not exactly linear, somewhat jumping from one example to another and a few digressions are almost confusing. It is rich in information and very good references, although a couple of imprecisions about Euclid and Pythagoras had me frowning. However, being not too long, this book manages to get the reader to understand the points made and never ceased to surprise and interest me.
I recommend this book to the non-mathematician interested in complexity and theory of networks. The book will be an ideal starting point for further reading.

Great Book! The amazing new science of networks made easy. *****
Buchanan makes the complex seem easy for the layman. The work of Watts and Strogats in discovering the mathematical proof of the the six degrees of separation concept is presented in an eminently readable and exciting way. This proof, and Buchanan's description of it, is powerful evidence of the value of networking for the majority of us who don't like it or feel it is a waste of time. I recommend Nexus to my audiences in every Power of Positive Networking Seminar I deliver; people who have read it from my classes are truly dazzled. Darcy Rezac: author, The Frog and Prince.

Great Book! The amazing new science of networks made easy. *****

Buchanan makes the complex seem easy for the layman. The work of Watts and Strogats in discovering the mathematical proof of the the six degrees of separation concept is presented in an eminently readable and exciting way.
This proof, and Buchanan's description of it, is powerful evidence of the value of networking for the majority of us who don't like it or feel it is a waste of time. I recommend Nexus to my audiences in every Power of Positive Networking Seminar I deliver; people who have read it from my classes are truly dazzled. Darcy Rezac: author, The Frog and Prince.