To describe is also to represent and interpret. All three concepts may stand one for the other. The object of this book is therefore to single out each of these moments of research, without providing any other meaning than a didactic one. Indeed, behind those three concepts (description, representation, and interpretation) are research prctices that, however different they may be, are complementary and raise specific questions and difficulties. This chapter explores them and serves as an introduction to a careful research. The favorite approach is both empirical and inductive: it starts with fielwork and then seeks to find a general logic. It strives to solve a specific puzzle without losing track of the matter of general interest it raises. The scientific debate is open to discussion and may hence go forth.