He has written on such topics as location theory, the provision and delivery of public and nonprofit services, urban development, and environmental policy. He was a fellow of the Center for Advanced Study in the Behavioral Sciences, a Guggenheim fellow, a Russell Sage fellow, and a SPIA fellow. He was elected to the National Academy of Sciences and as a fellow of the American Association for the Advancement of Science. He held offices with the National Research Council, the Association of American Geographers, the American Geographical Society, the American Collegiate Schools of Planning, and the Regional Science Association. As an adviser he has worked with the National Science Foundation, the U.S. State Department, the National Institute of Mental Health, and various departments of New Jersey government. Ph.D. University of Wisconsin.