Genetics, which integrates basic concepts of biology with clinical medicine, is assuming progressively increased importance in the understanding of disease. The medical community should be pleased, therefore, when new books on genetics appear, to fill the undoubted need for information.
However, authors should keep in mind the audience for which they write. Medical students will have lectures and other didactic exercises to elaborate the material in a book. Practicing physicians, however, do not ordinarily have lectures to fall back on. And practicing physicians comprise several groups, those whose knowledge of genetics is quite shaky, those who have had some training in the field, and those with substantial knowledge and sophistication. We may designate these groups as possessing elementary, intermediate, and advanced knowledge.
For whom is Dr. Knudson writing? His emphasis throughout lies on disease, rather than on the exposition of genetic principles. He keeps the clinical significance constantly in the