This series is intended for students and practitioners of the health profes­ sions who are seeking to expand their knowledge of computers in health care. Our editors and authors, experts in their fields, offer their insights into innovations and trends. Each book is practical and easy to use. Since the series began, in 1988, we have seen increasing acceptance of the term "informatics" and of the innovations it brings to health care. Today more than ever we are committed to making this series contribute to the field of healthcare informatics, the discipline "where caring and technology meet. " KATHRYN J. HANNAH MARION J. BALL v Preface Computer technology has transformed health care not only by improving the accuracy and quantity of information available to'clinicians, but also by improving the flow of information among the people who provide, arrange for, and pay for health services. This book is about the new computer networlcs that electronically link people and organizations in the health care field. Its purpose is to explore the impact of new computer networks upon the different organizations in the field, their services to patients, and the way in which organizations collaborate and compete, share information, and guard confidential material. The book explores computer networks primarily from the perspective of public health, discussing the impact that networks have upon communities as well as individuals.