The purpose of the present study was to investigate the influence of the real, environmental factor in the establishment of self, represented by the dependence of the baby on maternal care. We began, therefore, by mapping the discussions known as the Controversies through the history of the British Psychoanalytical Society, particularly after the death of Freud, caused by theoretical differences between Freud s daughter Anna and Melanie Klein, and focusing on the standpoint of the so-called Middle Group. In the ensuing scientific debates surrounding the Freudian legacy, the name of this group is representative of the fact that it positioned itself between the Anna Freudians and the Kleinians. One of its proponents, Donald Winnicott, was the main object of this study. As we sought to investigate the theoretical foundations that inspired Winnicott, we address the Freudian and Kleinian theoretical contributions, delving briefly into the major associated concepts. We then reflect basic differences established by the authors - Winnicott and Klein. The main concepts of Melanie Klein are the innate death instinct and the problem of the role of the environment in the emergence of ego. Winnicott s contributions were on the primitive emotional maturing process, particularly regarding the importance of the environment and dependence in the earliest stages of development, so as to highlight the theoretical innovations that the author brought to traditional psychoanalysis.