This paper offers an introduction to cognitive therapy which gives special importance to schemas of thinking in the expression of affect and behavior. Depression is a disease in which distorted and idiosyncratic patterns of thinking are activated; these are the major target of cognitive therapy. This therapy obeys specific laws and techniques based on scientific data and thus requires special training. The improvement of depression through cognitive therapy leads to the disappearance of depressive symptoms and the birth of adequate patterns for the management of psychic equilibrium. A plethora of publications emphasize the efficacy of cognitive therapy in the treatment of depression. This technique is in use, in Lebanon, in the Clinical and Research Service of Psychiatry and Psychology at St. Georges Hospital, Beirut.