When we started working in the field of human-computer interaction over ten years ago, there wasn't a field. We got strange looks from people who said "HCI isn't research; it's just common sense!" Now it is a fast-growing area of research and development. However, when we look around at advances in the field, we discover that many hard problems are still in front of us.

The theme of this series is the cooperation between behavioral scientists and computer scientists in developing human-computer interfaces. Recognition of the need for multiple roles in interface develop-
ment has led to increasing diversity in this field. We welcome this as a positive indication of the contributions that a wide variety of perspectives can bring to bear on the open issues of the field. This diversity is reflected in the present volume, which includes technology, methodology, techniques, case studies, applications, user support, and tools. This is a nice continuation from Volume II, in which we stated in the preface that cooperation was needed in all the major areas of current work. Theory, modeling, methodologies, tools, and evaluation were included in Volume II; all those same topics plus technology and case studies are now addressed in this volume.