Applied Geometry � American Scientist:
"HOW ROUND IS YOUR CIRCLE?: Where Engineering and Mathematics Meet. John Bryant and Chris Sangwin. xxii 306 pp. Princeton University Press, 2008. $29.95.
The great power of computers to model various aspects of geometry and mechanics has made it possible to visualize things quickly and in useful and innovative ways. But nothing beats the construction of a physical model. And when the model conforms exactly to the mathematical prediction, it is very satisfying. How Round Is Your Circle?, by John Bryant and Chris Sangwin, is a guide to making physical models of various phenomena of geometry that are related to serious applications, both historical and contemporary. The mathematics required is elementary: standard geometry and trigonometry, with occasional bits of calculus."