caliber, ranging from excellence beyond their comprehension to insufferable mediocrity. Textbooks in en­ docrinology that are simple enough to cover the principles of that speciality and yet comprehensive enough without treading into controversial quicksand are few and far between. This book is aimed at filling that gap and is written with no other criterion than simplifying a complex subject matter. From this touchstone, the work has never really departed. A decade of experience as a teacher and physician in the field of endo­ crinologyhas impressed on me that the process of "simplification" rests on four basic principles: an understanding of endocrine concepts, the application of these concepts to the understanding of diseases, the transference of knowl­ edge to clinical situations, and the integration of the patient with the labo­ ratory, the ultimate testing ground where clinical diagnoses stand or fall.