This book fills a hiatus in our medical history for it is the first complete biography of an unusually productive man. Thomas Duhring (1845-1913) described pruritus hiemalis and dermatitis herpetiformis, the latter commonly called Duhring's disease. He was the son of immigrants; his father was from Germany, and his mother was from German speaking Switzerland. Although from modest origins, his father, by virtue of industry and intelligence, became one of the ten richest men in Philadelphia. Thus it was financially easy for Duhring to spend two years in sundry dermatology centers in Europe. He was an exceptional teacher and a very prolific writer. We are told that his descriptions were accurate and precise. Yet he described one patient as being clay-colored. I wonder what color he meant; for Merriam Webster gives clay colored as "yellowish red yellow in hue" and the Encyclopaedia Britannica refers to white, red, blue, and gray