Kenzie L. Preston is a Senior Investigator and Chief of the Clinical Pharmacology and Therapeutics Research Branch at the National Institute on Drug Abuse Intramural Research Program (NIDA IRP). She has been conducting drug abuse research in illicit drug users since 1982 when she completed Ph.D. training in pharmacology and began a post-doctoral fellowship in the area of human behavioral pharmacology at the Department of Psychiatry and Behavioral Sciences at Johns Hopkins University School of Medicine. Since 1991 she has been conducting substance abuse treatment research at the NIDA IRP. Her major research interests are the development and testing of substance abuse treatment and the use of ecological momentary assessment (EMA) and real-time location (GPS) data to investigate the process of relapse. She has extensive experience with drug use monitoring with biospecimen analysis, abuse liability assessment and conducting clinical trials of substance abuse treatment.