A. -Let V be a complex nonsingular projective 3-fold of general type. We prove P12(V ) := dim H 0 (V, 12KV ) > 0 and Pm 0 (V ) > 1 for some positive integer m0 24. A direct consequence is the birationality of the pluricanonical map m for all m 126. Besides, the canonical volume Vol(V ) has a universal lower bound (3)
