An Introduction to Population Genetics is intended as a text for a one-semester biology course in population genetics at the undergraduate or graduate levels. The goal of the book is to introduce both classical population genetics theory developed in terms of allele and haplotype frequencies and modern population genetics theory developed in terms of coalescent theory. Numerous applications of theory to problems that arise in the study of human and other populations are presented. Appendices provide the mathematical background necessary to understand the basic theory.