We are used to calling most developing countries overpopulated and consi­ dering some industrialized countries (like West Germany) "threatened by underpopulation". Analogous population policies with different objecti­ ves are discussed. However, none of the measures suggested can be justi­ fied or evaluated without an implicit concept of optimum population, a notion which has attracted attention ever since economics was made a science. The relevance of the subject and the recent rise in interest by popula­ tion economists has motivated the organization of a conference on "Opti­ mal Population" in Bielefeld, where most of this book originates. Finan­ cial support for the conference and the publication of this book by the Thyssen Foundation and the editorial help provided by John De New and Contents Optimum Population: An Introduction K. F. Zimmermann. I. Optimal Size and Growth Rate of Population Socially Optimal Population Size and Individual Choice M. Nerlove, A. Razin, and E. Sadka. 19 Endogenous Population With Discrete Family Size and a Capital Market D. Leonard.