Perhaps on no other single subject does such an enormous and complex literature exist as for Diabetes Mellitus. Yet in the past year the well-known and often highly distinguished members of a Workshop, sponsored by the United States Public Health Service and other bodies, frankly admitted their ignorance both of the etiology of this common illness and of the prevention and treatment in childhood of related problems of emotional upset and adjustment. When men of the stature of Mirsky say, "I do not know what the aetiology of diabetes is or what the pathogenic mechanism is," and others of the experience of Danowski express the hope that "we will generate approaches, techniques and specific plans to relieve our ignorance," we get an insight into the intricacy of the problem.