With estimates of their numbers ranging from one million to almost four million people, allied health care personnel make up a large part of the health care work force. Yet, they are among the least studied elements of our health care system. This book describes the forces that drive the demand for and the supply of allied health practitioners--forces that include demographic change, health care financing policies, and career choices available to women. Exploring such areas as credentialing systems and the employment market, the study offers a broad range of recommendations for action in both the public and private sectors, so that enough trained people will be in the right place at the right time.