I thoroughly enjoyed Math Hysteria and How to Cut a Cake, and was looking forward to Ian Stewart's Cows in the Maze. Unfortunately, this book is rather disappointing. The other two books are filled with lesser known topics in recreational maths that are nevertheless very interesting and treated in quite some depth. Stewarts engaging style of writing encourages you to start thinking about the problems that he discusses yourself.
Cows in the Maze is very different. There are 21 chapters. Six deal with topics you will encounter in many other books (Hex, the distribution of prime numbers, incorrect reasoning in the legal system, knight's tours, the Klein bottle, and magic squares), and six are really on physics and not on mathematics (three chapters on time travel, one on the shape of drops, and one on self-organized criticality, one on real knots ). More disappointing however is the way the topics are treated. Many chapters are very superficial. The chapter on Hex is a good example. It only discusses bridge and ladders, which can both be explained in one or two sentences, and anyone starting to play the game will discover these things for himself after a few minutes. Other chapters give too little information to enable you start working in the problems yourself. It is, I think, telling that the feedback section of many chapters is quite small or even absent.
On the other hand there is too much stuff that I could have done without. In the chapter on the way quadrupeds walk, the main topic seems to be Tarzan and Jane. Also in the chapter on the shape of drops the story distracts too much from the mathematics. Klein bottles made of glass look nice, but it is not really mathematics. The chapter on self-organized criticality could do with the incomprehensible quotes from the people involved in arts. And the last chapter I found very interested, but I fail to see what it has got to do with dancing.
If you don't have Math Hysteria and How to Cut a Cake, buy them and forget about Cows in the Maze.