A good friend's son, age 10, has been assigned this book (alongside another title by the same author) in school, presumably in addition to the normal math he gets given to study. My friend is very smart, she studied at Cambridge, but her math is no longer what it was twenty years ago, so on the strength of the fact that I still (very occasionally) find myself pushing symbols for a living I was drafted in to have a look. I ordered the books and reported back that I was about to start reading.
"What do you think" she enquired.
I had to be honest: "No idea why they're assigning books for dumb adults to smart kids" was my first reaction, and I told her as much, but I had not read the book yet and I promised to revert once I had.
I'm now done reading it. I found it roughly speaking to be the equivalent of playing backgammon against my i-Phone. So it entertained me, basically, but I am no richer for having read it. I've learnt nothing, I obtained no new insights on stuff I already knew and I'm kind of lamenting the time I spent reading it, but since I read it in the crowded tube (4 round trips between Earls' Court and Liverpool St) it was time that could not have been dedicated to serious reading anyway. Bottom line, if you already know math this is a bad "popular mathematics" book because there's nothing in here that will leave you stumped and I found zero fresh perspective or twists on interesting problems.
Needless to say, the book was not assigned to me, it was assigned to my friend's son. It's in my view inadequate from his angle as well, because the author has an annoying habit of describing a problem and then pulling the answer out of a hat. Only about half the problems are worked out, perhaps fewer, the rest don't even get worked out in an appendix. Now, I don't expect the 7 bridges of Koenigsberg to be solved in the appendix, but there's a large number of instances here where I've felt like whipping out a red pen and scribbling "show your work" all over the place. A self-study guide this ain't. Whoever assigned this book to 10-year-olds had better also hand out to them a good thirty extra pages with detailed solutions. Meantime, I fear I'll have to, or else the paedagogical value of the book shrinks significantly.
"But the book was aimed at neither yourself nor your friend's precocious son" I hear you say. It's a popular mathematics book and should be rated as such.
Very well, then, here's my summary of where it ranks in that respect. If I had to give Timothy Gowers' "Very Short Introduction to Mathematics" or Conway's "Book of Numbers" a 5/5, then "Why do Buses come in Threes" deserves a 3/5. It explains and inspires far less than either, but it's not too bad.
Finally, if I had to rate the book for how it makes innumerate people feel about themselves, on the strength of the rave reviews listed here it's got to be very good; everyone seems to be giving it five stars....