Zolpidem, zopiclone, and zaleplon are commonly referred to as the "Z-drugs." The Z-drugs are nonbenzodiazepine hypnotics indicated for the short-term treatment of insomnia. Since becoming widely prescribed as sleep aids in the United States, they are increasingly being detected in a variety of forensic specimens. We present a comprehensive overview of the basic chemistry, pharmacodynamics, and pharmacokinetics of zolpidem, zopiclone, and zaleplon, including their interaction with other prescription drugs and ethanol, findings in drug-facilitated sexual assault (DFSA) casework, and methods of analysis.