Shortly after the final classification of all endo-trivial modules for a finite p- group P by Jon Carlson and Jacques Thévenaz, the complete classification of all endo-permutation modules was obtained by Serge Bouc (The Dade group of a p-group, Inventiones Mathematicae 64 (2006) 189-231). The purpose of this paper is to give an overview of this subject, as well as a survey of the steps of the proof and of the various techniques involved in the classification.