Over the past twenty years an increasing number of researchers from various universities have been investigating motivational issues underlying the self-regulation of behavior. Using either Self-Determination Theory or closely related theoretical perspectives, these researchers have performed laboratory experiments, as well as field studies in a variety of real-world settings, including education, work, parenting, health care, sport, and protection of the environment. In April 1999 thirty of these researchers convened at the University of Rochester to present their work, share ideas, and discuss future research directions. The Handbook of Self-Determination Research is an outgrowth of that important and fascinating conference. It summarizes the research programs of these social, personality, clinical, developmental, and applied psychologists who have a shared belief in the importance of self-determination for understanding basic motivational processes and for solving pressing real-world problems. Eighteen chapters, including an overview of self-determination theory, present the current state of the research in this scientifically rigorous, yet highly relevant, approach to studying motivational problems in various life domains. Researchers from eighteen universities in the United States, Canada, and Germany present concise and up-to-date accounts of their research programs concerned with the self-determination of human behavior. In these chapters, scholars also consider the relevance of the research on self-determination to other areas of inquiry such as coping, self-esteem, and interest. Edward L. Deci and Richard Ryan are professors of psychology in the University of Rochester's Department of Clinical and Social Sciences in Psychology.