In a somewhat truistic, philosophical discussion, the author draws a parallel between grief, its etiology, effects on the individual, and predictable outcome, and physical diseases. On the basis of a psychological fulfilment of 'Koch's postulates', he then justifies his conclusion that grief is a disease. With a technique not unlike that used by Freud in the earlier metapsychological papers, a series of straw men are then erected and leveled in short order. Satisfying himself that his point has been established, Engel then concludes that one can include the actual or threatened loss of a loved object as an etiologic factor of importance along with other 'major noxae, e.g., physical agents, micro-organisms, etc.'. This leads to a greater stress on the role of the central nervous system in the production of all forms of disease, and suggests that the environment, made up of other significant psychic objects, may be an important factor in the pathogenesis of other disease entities. Finally, he states that the maintenance of