Book excerpt: The purpose of the Handbook is to provide systematic overview of medical and health informatics for health care professionals and for students in medicine and health care, who will be the clinical professionals of the next millennium. Health care professionals will use computers to support patient care, assess the quality of care, and enhance decision making, management, planning, and medical research. Computer-based patient records and electronic communications will be the most visible developments in the years ahead. The Handbook has been written by a host of renowned international authorities in medical and health informatics. The editors took much care that the Handbook would not be merely a collection of separate chapters, but rather would offer a consistent and structured overview.