In the Preface to the third volume, we described the evolution of this Series and the changes that have taken place in the field since the first volume appeared. The contents of the current volume continue the com- mitment to a broadly based perspective on research related to con- sciousness and self-regulation which was embodied in the previous three volumes. Chapters are included which consider the role of con- sciousness in cognitive theory and clinical phenomena. Several of the contributions to this volume are concerned with the nature of self-reg- ulation and the role of conscious processing in the mediation of self- regulated behavior. Most of the authors adopt a psychobiological ap- proach to their subject matter. Our selection of contributors with a bias toward this approach reflects our own views that the psychobiological approach is a very fruitful one and that the "architecture" of the nervous system places important constraints on the types of theories that are possible in this emerging area. While the subject matter of the chapters in this volume is quite diverse, the contributions are united by their emphasis on the impor- tance of consciousness and/or self-regulation in the understanding of behavior and experience. We have selected what we believe is repre- sentative of the best theory and research in the diverse areas which bear on the theme of this series, maintaining a balance between basic and clinical research.