Starting from Kraepelin’s concept of “fundamental states”, but employing the classical term of temperament, the authors focus on “affective temperament” as a specific constitutional disposition, a dimensional construct; only the extremes can be considered abnormal in statistical and perhaps in a clinical sense; he proposed some criteria for a better and shared definition of the affective temperaments in accord with Akiskal views. In modern classifications the term “Major Depression” replaced the terms of melancholia and endogenous (the reference to the endogenous has been abandoned because its theoretical implications). Melancholia has been considered “a term of the past”, used, in this manual, to indicate a typically severe form of depression that is particularly responsive to somatic therapy; the criteria of DSM are conceived in order to define a sub-classification (Major Depressive Episode with Melancholia). According the authors, the temperament still has an important role in determining the clinical picture of the affective episodes and the longitudinal course of the illness.