Certain basic theoretical differences between Freud and Klein are reviewed. The transition from Freud to Melanie Klein is first manifested by a change of emphasis from the drive to the object. Another issue is the fact that Freud never fully adopted the concept of introjection. For Melanie Klein, on the contrary, the object is inseparable from the operations which relate to it, such as splitting, introjection and projection. The internalized object is presented as something which is beneath multiple representations and affective states. It never appears directly but through images, concepts, memories, anxieties, or wishes which change ad infinitum. Melanie Klein's work on the formation of the superego reveals that it is constituted by the approximation of two nuclei, quite contradictory in the beginning but similar in their object-oriented nature, the persecutory breast and the idealized breast. The object appears for Melanie Klein at the