Dr Crossley is Professor Emeritus of Pharmacology at the University of Maryland at Baltimore Dental School. A native of Rhode Island, Dr Crossley received a BS in Pharmacy from the University of Rhode Island in 1964. He later was awarded the MS (1970) and PhD (1972) in the area of Pharmacology. The University of Maryland Dental School in Baltimore awarded Dr Crossley the DDS degree in 1980. He is the Director of Conjoint Sciences and Preclinical Studies at the School of Dentistry and maintains an intramural part-time private dental practice. Dr Crossley has co-authored a number of articles dealing with law enforcement on both a local and Federal level. This liaison with law enforcement agencies keeps him well acquainted with the “drug culture”. He has been appointed to the Governor's Commission on Prescription Drug Abuse and the Maryland State Dental Association's Well-Being Committee. Drawing on this unique background, Dr Crossley has become nationally and internationally recognized as an expert on street drugs and chemical dependency as well as the clinical pharmacology of dental drugs.