This book focuses on the ideas and techniques characteristic of different approaches to the study of ecology. Ecology is made up of a number of distinct disciplines; each of our authors, an expert in a specific kind of ecology, speaks for the distinctness of that specialization. We discuss the relationship of people and nature, and six kinds of ecology: ecosystem, physiological, behavioral, population, and community. For each kind of ecology, we explore how it is unique, the appropriate theory and technology, the kinds of questions asked, and the successes and possibilities for the future. This discussion is set in a context of the human relationship to nature, with an emphasis on practical applications of ecology. This text is unique in that it presents ecology as being composed of a number of different ways of knowing, seeing, or asking questions. We focus on the kinds of questions ecologists ask about their world, rather than on accumulated ecological knowledge. This text is for students who have taken an introductory biology course and are ready for an overview of general ecology, a user’s guide to ecology that will help readers understand the diversity of the field and navigate the sometimes tricky currents among the subdisciplines. Each chapter is a gateway, not an advanced course in itself. Our goal is to communicate our excitement about ecology and to provide readers with a basis for continued learning in the area of ecology. The book can be easily read in one semester, allowing students to grasp the distinctions among the various kinds of ecology, and to use these distinctions, for example, to analyze scientific papers, to know what different kinds of ecology can do and what they are inappropriate for, and to express how different kinds of ecology can be used to answer ecological questions.