The author of this work is Professor of the History of Medicine in the Johns Hopkins University. In order to evaluate his book, it is necessary to know something of the qualifications of the author. Professor Sigerist regards medical history to a large extent as economic history. He states this concept elsewhere (Bull. Inst. History of Med., 1936, vol. 6) in the following terms: 'The history of medicine in a very large sense is the history of the relationships between physician and patient, between the medical profession in the largest sense of the word (including administrators, public health officers, scientists, nurses, priests, quacks, etc.) and society'. In another passage he adds, 'The history of hygiene is not only determined by scientific ideas but just as much by educational ideals, and public health can only develop under favorable political conditions'. Professor Sigerist consequently regards the history of medicine as a subject of broad and important scope.