*The Joy of Π*, David Blatner, 1999, 130 pp. $12, paper. ISBN 0-8027-1332-7. Walker and Company, 104 Fifth Ave., New York, NY 10011. http://www.walkerbooks.com

What a delightful book! I received *The Joy of Π* as a Christmas present, began reading it and could not put it down until I finished. In recent years, there has appeared a spate of books on pi. I have read most of them. While these books have been informative and useful, this is the most “information packed” and enjoyable one that I have encountered. Filled with history, quotes, anecdotes, visual excursions and π trivia, including an impressive one million decimal expansion of the number, this book leads the reader through a mathematical adventure. Starting from the obvious question, “Why Pi?”,

Blatner then takes us through a comprehensive history of the appreciation and computational development of π as a mathematical constant, or the “ultimate fake random number” as it is perceptively described.

Writing as a mathematician and computer scientist, the author baits and tantalizes his readers with the quest to find another digit in this number’s mysterious continuing decimal sequence. “Is there a pattern in the numerical entries?” The saga of the reclusive Chudnovsky brothers as they seek one by grinding out billions of digits on their supercomputer is related. This search continues unfulfilled.

I was amazed, intrigued and gratified with all the new discoveries I learned about pi . Did you know that: the first 144 digits of pi add up to 666; or that the height of an elephant is given by 2X П X (diameter of its foot)? The symbol for pi, π, was popularized by William Jones in 1706, not by Leonard Euler! Circle squares are called *tetragonidzein* or cycometers. I could go on with more wonderful facts but experience the joy of π yourself and read this book. It is recommended for all mathematically interested readers from high school students upwards.

Note that there is now a website connected to this book. See the review of the website, with a link, in Convergence.

Frank J. Swetz, Professor Emeritus, The Pennsylvania State University