This successful text examines the ecological processes that determine the size and structure of a population, and demonstrates that there are many fundamental principles that apply to populations of both animals and plants. The authors have sought to involve the text in areas where particular progress has been made and consolidated. The third edition therefore addresses the problem of the detection of chaos, buried sea-banks and herbivorey implants and looks more closely at the role of spatial scale in two-species interactions. It also introduces a major new section on the concept of the meta-population. The book is designed to be readily understood by undergraduates with little or no previous knowledge of the subject, and also to stimulate wider debate and discussion.