This book presents plane geometry following Hilbert's axiomatic system. It is inspired on R. Hartshome's fantastic book Geometry: Euclid and Beyond, and can be considered as a careful exposition of most of chapter II of that book. It must be remarked that non-euclidean geometries, i.e. geometries not satisfying the fifth postulate of Euclid, enter the scene, in a natural way, from the very beginning. The vast majority of plane geometry texts are only concerned with euclidean geometry, loosing the oportunity of not only teaching rigorous reasoning to freshmen, but at the same time exposing them to the mind expanding experience of contemplating the strange geometries conceived, in the first decades of the XIX century, by Gauss, Lobachevsky and Bolyai.

Carlos Alberto Cadavid Moreno: Doctorado University Of Texas System Ph D. 1990-1998. Maestría/Magister University Of Cincinnati - Master In Science. 1988-1990. Pregrado/Universitario Universidad Nacional de Colombia - Sede Medellín - Matemáticas. 1983-1988.