Clarifying the scope and limitations of virtual screening, this book explores the algorithms involved and how to use them, offering easy access to strategies and techniques for lead discovery. Part I offers perspectives on ligand-based and docking-based virtual screens, framing the challenges facing the field. Part II covers the choice of compounds best suited as drug leads and Part III discusses ligand-based approaches. Part IV outlines some important and practical considerations relating to the energetics of protein-ligand binding and target-site topography. Part V discusses specific docking algorithms and strategies.