Drug Metabolism Letters publishes letters and research articles on major advances in all areas of drug metabolism and disposition. The emphasis is on publishing quality papers very rapidly by taking full advantage of the Internet technology both for the submission and review of manuscripts. The journal covers the following areas: In vitro systems including CYP-450; enzyme induction and inhibition; drug-drug interactions and enzyme kinetics; pharmacokinetics, toxicokinetics, species scaling and extrapolations; P-glycoprotein and transport carriers; target organ toxicity and interindividual variability; drug metabolism and disposition studies; extrahepatic metabolism; phase I and phase II metabolism; recent developments for the identification of drug metabolites.