This volume includes information on recent advances in five important areas: an account of inhibitors of the caspase family of proteolytic enzymes that represent a new class of anti-inflammatory and antiapoptotic agents of potential value in rheumatoid arthritis; and a survey of semi-synthetic and totally synthetic antibiotics and anti-HIV agents and their sites of interaction; the development of inhibitors of the intracellular enzyme acyl-CoA: cholesterol O-acyltransferase (ACAT) for the treatment of hypercholesterolemia; a description of recent progress in growth hormone secretagogues, with the focus on strategies to improve oral bioavailability and duration of action; and information on inhibition of the proteolytic enzyme, hepatitis C protease N-3(NS3), (required for vital replication) as one of the most attractive targets for HCV infections.