In the April issue of the Journal (121:363, 1971) the book review by Eugene V. Perrin, MD, should have had two books listed at its head. The book omitted (to be placed at head of first column on page 263) is as follows: Mendelian Inheritance of Man: Catalogs of Autosomal Dominant, Autosomal Recessive, and X-Linked Phenotypes, ed 2. By Victor A McKusick, MD. Price, $10. Pp 521. Johns Hopkins Press, Baltimore 21218, 1968.