Perelman I. and . Entertaining geometry - In the free air and at home 3 editions . 1929 [pdf 242sc 238+2c. 47. This book is written not so much for friends of mathematics, but for her enemies. She is referring mainly not to those who already have a penchant for mathematics, and not to those who have not yet begun to study it at all. The author targets the book most of all for the vast category of readers who got acquainted with this science at school (or are still getting acquainted with it) without much interest and animate, having only cold reverence for it at best. To make geometry attractive to them, to inspire hunting and to cultivate a taste for its study is the direct task of this book...