This meeting was sponsored by the National Institute of Justice's (NIJ's) Office of Research and Evaluation, in partnership with its Office of Investigative and Forensic Sciences. The concerns of the meeting were occasioned by growth in the diversion and illegal use of prescription drugs, changes in medical and other marijuana-use legislation, and the evolution of novel psychoactive substances. Meeting objectives included the dissemination of information to practice experts on current projects, the exchange of information with other agencies, and the solicitation of feedback that will inform Federal plans for future research that are responsive to the field's information and practice needs. The 1-day meeting was structured to solicit feedback to presentations by representatives of the National Highway Traffic Safety Administration, NIJ, and the National Institute of Drug Abuse. These presentations were followed by a roundtable discussion that included States and local practitioners and Federal experts. Topics covered addressed many aspects of drug recognition and impairment practice, including the detection and quantitation (purity) of drug seizures; forensic toxicology post-use; reliable measurement of impairment caused by illegal drugs; investigative leads for case building; the collection and submission of drug evidence for laboratory analysis; tools for drug detection in the field; expert witness testimony; confirmation of toxicological and chemical analysis; and protocols for prosecution and court case management.