"Students of medicine," it is worth pointing out, does not mean the same as "medical students." The latter, by definition, are trying to acquire their medical degree. The student of medicine, on the other hand, may be an active practitioner, but one who seriously concerns himself with the theories of medical science. We may indeed hope that medical practitioners remain lifelong students of medicine.
Any immunology book that aims at "students of medicine" faces a dual audience. The undergraduate who approaches the subject for the first time will presumably have a course of lectures and an instructor to explain any difficulties, and elucidate obscurities. The graduate practitioner, on the other hand, who has some out-of-date acquaintanceship with the subject and who wants to keep up with modern concepts, will not ordinarily have such an instructor but must derive his knowledge the hard way, from the printed page alone. The present