Virtual screening can reduce costs and increase hit rates for lead discovery by eliminating the need for robotics, reagent acquisition or production, and compound storage facilities. The increased robustness of computational algorithms and scoring functions, the availability of affordable computational power, and the potential for timely structural determination of target molecules, have provided new opportunities for virtual screening, and made it more practical. Why then, isn"t everyone using virtual screening? Examining the scope and limitations of this method, "Virtual Screening in Drug Discovery" explores the algorithms involved and how to actually use them. Part I offers perspectives on both ligand-based and docking-based virtual screens. The authors of these chapters frame many of the challenges currently facing the field. Part II considers the choice of compounds that are best suited as drug leads. Part III discusses ligand-based approaches, including descriptor-based...