This book is organized in nine parts, as follows. Part I, "Preface," includes an account of how the author went from the rather esoteric research on theoretical problems in serial rote learning to research on the inheritance of mental abilities and its implications for education. Part II, "How Much Can We Boost IQ and Scholastic Achievement?," is a reprint of an article which originally appeared in the "Harvard Educational Review," 1969. 39, pp. 1-123. Part III, "A Theory of Primary and Secondary Familial Retardation," is a reprint of an article which originally appeared in the "International Review of Research in Mental Retardation," 1970, 4, pp. 33-105. Part IV, "Estimation of the Limits of Heritability of Traits by Comparison of Monozygotic and Dizygotic Twins," originally appeared in "Proceedings of the National Academy of Science," 1967, 58, pp. 149-156. Part V, "IQs of Identical Twins Reared Apart," originally appeared in "Behavior Genetics," 1970, 1, pp. 133-148. Part VI, "Genetic Research on Human Mental Abilities: Ethical Issues," originally appeared in "The Humanist," January-February, 1972, pp. 5-6. Part VII, "A Note on Why Genetic Correlations Are Not Squared," appeared originally in "Psychological Bulletin," 1971, 75, pp. 223-224. Part VIII is a bibliography of articles about "How Much Can We Boost IQ and Scholastic Achievement?". Part IX is a bibliography of articles on genetics and individual differences, by Arthur R. Jensen. (JM)