For almost fifty years, Mark H. Haller had been a historian of illegal enterprise-more commonly known as organized crime-in urban America. He is the author of an introduction to the now classic work by John Landesco in Organized Crime in Chicago (University of Chicago Press, 1968). Haller passed away in 2012.

Matthew G. Yeager obtained his bachelor's degree in criminology from the University of California at Berkeley in 1972. He was introduced to the work of Mark H. Haller and John Landesco during this time. His master's degree is from the State University of New York at Albany (1975), and his doctorate in sociology is from Carleton University, Ottawa, Canada (2006). He has published over thirty articles and studies in theoretical and applied criminology and is a practicing clinical criminologist in sentencing alternatives. He is currently associate professor in the Department of Sociology at King's University College, part of Western University-Canada. He lives in London, Ontario.