Top critical review
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Little about group theory; lots about mattresses
on October 22, 2009
I was disappointed in this book. Its title suggests that it will contain recreational mathematics, but it contains almost no mathematics at all - not a single equation. Group theory is a subject that has been covered extensively in recreational mathematics, and the author chooses to illustrate it using the symmetries of rotating a mattress. On the way, he ruminates extensively on the subject of mattresses. If you don't know what a "group" is now, after reading this book you will be none the wiser, if you do know, you will wonder why he says so little about the subject. You will learn a lot about how different manufacturers recommend you turn their matresses, but I didn't care before and still don't.
I have similar problems with the other chapters; he interweaves the theory of gear ratios in clocks with that of rational approximations (a natutal fit) but never really explains the mathematics, and instead its more of a story about how he tracked down the original historical sources of where gear ratios were first calculated ...
The chatty and informal style would have worked better in a magazine column, which is where these came from.
If you want a book about mathematics which itself contains virtually no mathematics, and you want something light and easily read, which covers a wide range of topics, sure.
If you know what a "group" is (or a continued fraction) and want to see if he brings a new twist to these old subjects, I think you will be diappointed.