**Stimulating collection of unusual problems dealing with congruence and parallelism, the Pythagorean theorem, circles, area relationships, Ptolemy and the cyclic quadrilateral, collinearity and concurrency, and many other topics. Challenges are arranged in order of difficulty and detailed solutions are included for all. An invaluable supplement to a basic geometry textbook.c**

Challenging Problems in Geometry (Dover) – Posamentier . Salkind