When I was a teenager I delighted in Martin Gardner’s books like Mathematical Puzzles and Diversions, taken from his Scientific American columns. British mathematician Ian Stewart has taken over Gardner’s role and continues to amaze and boggle the mind with the possibilities of recreational maths in his latest collection.
For me it was rather a mixed bunch. The best were great fun – the worst would only really engage the sort of person who thinks calculating pi by hand is a form of entertainment. I think to some extent Stewart has a problem because Gardner had already picked off the really entertaining, truly amazing stuff, and Stewart is left with either more of the same, or things that aren’t so engaging. Even so it’s an enjoyable read for anyone who finds mathematical puzzles fun – just be prepared to skip over one or two bits.
In a few of the sections Stewart adopts a story-telling form, and these are the weakest, as he’s not a great fiction writer and the result is too whimsical and irritating. Having said that, his three part story approach to time travel is interesting, if rather limited, but would have been so much better without the H. G. Wells pastiche.
In many of his books, Stewart is excellent at explaining obscure maths to the general reader, but for this one I think he assumes just a bit too much knowledge, and his explanations (for example of the symmetry breaking in animal gaits) can be quite confusing. This was particularly unfortunate in his ‘interrogators fallacy’ section where he tries but fails to explain why some arguments used in trials don’t hold up statistically. This chapter needs totally re-writing.
Despite these concerns, there’s much to interest the recreational maths fan. I was delighted to see a piece on what he refers to as ‘bends’ but are what normal people call knots. He has to do this because it’s a classic case of mathematicians living in their own tiny and often irrelevant worlds – according to the standard mathematical definition, a knot is in an infinitely thin line and both ends of the line are joined up. That is not a knot, guys. But this piece by Stewart deals with the maths of real knots.
A mixed bag, then, but there’s enough really good stuff in here to allow it four stars and to suggest than any recreational maths enthusiasts would be mad not to add a copy to their bookshelves.