William W. Greenhalgh was both a professor of law at Georgetown University Law Center teaching Constitutional Criminal Procedure and the director of the Prettyman-Stiller Legal Fellowship Program in the graduate school of the Law Center from 1963 until his death in 1994. In 1974, Prof. Greenhalgh became director of the Criminal Justice Clinic at Georgetown, serving in that capacity until his death. He was widely regarded as a pioneer and champion of clinical legal education. The author of many articles and books, Prof. Greenhalgh was considered a leading authority on the Fourth and Sixth Amendments to the U.S. Constitution.