I have for a number of years taught a course in population genetics for students interested in plant and animal breeding. The objective of the course has been to lay a foundation in population genetics for the concepts of quantitative genetics which are introduced in the last third of the course. I have not been able to find an appropriate text for this purpose. For a quarter of a century, Falconer's Introduction to Quantitative Genetics has been the standard, and excellent, text in that subject. For my purposes, however, this text is not sufficiently detailed in the population genetics basis for quantitative theory. A number of good texts in population genetics are available, of which Li's First Course in Population Genetics is didactically the best. But these texts are directed toward the genetics of natural populations, rather than domestic populations, breeding under human control. They also tend to treat quantitative genetics gingerly, if at all. I have therefore developed the present text from my teaching notes. The chapters of this book are labeled Lectures. Each is intended to correspond approximately to the amount of material which can be covered in a 50-minute lecture. Divisions are, of course, dictated by the natural divisions of the subject matter, and the lectures are therefore not of uniform length. Nevertheless, in so far as possible, an attempt has been made to make the average length a lecture's worth.