This book represents the outcome of the lectures given by the author at the University of Aix-Marseille and the numerous articles written by him in relation to the course. Its main aim is both didactic and heuristic. For each subject it proposes, in a systematic way and with a good number of schemes, new answers to traditional questions. The emphasis is on two fields: on one hand the relations and correlations between so-called "derived" verb classes, the syntax and semantics of which are entirely revisited, and, more generally, the question of lexical derivation in Classical Arabic; on the other hand, semantic and pragmatic values of the inflected verbal forms, of which a purely "relativist" view is proposed.