Nets, Puzzles and Postmen
Higgins is the inventor of Circular Sudoku, and the book looks at how to deal with this, and several other puzzles and games, in terms of networks. There is also a look at some of the more traditional problems of network theory. How many colours do you need to colour a map? If you have a network of roads, what is the best way from A to B? What if you want to make it into a one-way system?
One thing Higgins emphasises in the book is that recasting a problem into a different form may often be the best way of tackling it. For instance the problem of matching workers to suitable jobs may be recast as a problem of how much water can flow through a network of pipes.
If you're looking for a bit of light reading then I wouldn't really recommend this book, since to get best out of it you need to work through the examples and demonstrations which Higgins gives. On the other hand it isn't a textbook, and this is the sort of mathematics for which you don't need prior experience. I feel that it would suit anyone who is fairly keen on maths (or programming) and would like to find out about this useful subject.