My motivation for writing this book was to provide a text for new researchers in ecology, giving a framework for understanding methodological issues, and helping them to define and plan research. In the late 1980s I started teaching a graduate course in research methods at the University of Washington. My faculty colleagues were concerned that students were having dificulty writing research plans. At the same time statistical consultants were spending much time asking students to clarify their study objectives and logic of investigation before statistical advice could be given. Discussions with colleagues at other universities suggested that these were not unusual circumstances.

Problems with ecology and its methods are also encountered by established researchers and there have been substantial criticisms of the subject and its research methods. Concern has been expressed that there has been a lack of progress in ecology, that no general theory has emerged, that ecological concepts are inadequate, and that ecologists fail to test their theories (Chapter 16). While some of this criticism may be justified, the students' needs required me to look beyond it and seek ways of being constructive. This has required making two distinctions that are fundamental to the way this book is written.

The first distinction is between methods of reasoning such as how we use logic, construct a hypothesis and develop a theory, and techniques of investigation, such as an experiment, or a survey, or constructing a simulation model. Much of this book is about methods of reasoning for ecological research and how they can best be used with particular techniques of investigation.