The first chapter is about spices, whose active parts are very similar chemically, describing Other chapters look at medical molecules, inlcuding the pill, quinine, antibiotics and vitamin C - so important for long sea journeys. There are also chapters on salt - once so valuable it was used as money - and sugar, which played a central part in the slave trade. Often the story concerns looking for artificial forms of natural substances, such as rubber, dyes and nylon. There are also substances which have mixed benefits such as nitro-explosives, pollutants such as chlorocarbons and addictive substances such as nicotene and morphine (and even caffeine). The book also show how certain hallucinogens may explain some of the claims of witchcraft. Note that there isn't actually a chapter on Napoleon's button, tin being an element rather than a compound.
The book is easy to read (as long as you're not scared by chemical diagrams), but also very informative. It explains the chemistry of well known substances, describes important trends in history, and points out the links between the two. Highly recommended