How do plant and animal populations change genetically to evolve and adapt to their local environments? How do populations grow and interact with one another through competition and predation? How does behaviour influence ecology and evolution? This second edition of Dick Neal's unique textbook on population biology addresses these questions and offers a comprehensive analysis of evolutionary theory in the areas of ecology, population genetics, and behaviour. Taking a quantitative and Darwinian perspective, Neal uses mathematical models to develop the basic theory of population processes. Key features in this edition include new chapters on inbreeding and species interactions and community structure, a modified structure in Part II, more recent empirical examples to illustrate the application of theoretical models to the world around us, and end-of-chapter problems to help students with self-assessment. A series of spreadsheet simulations have also been conveniently located online, for students to further improve their understanding of such models.