Preface.- List of Contributors.- Engineering G Protein-Coupled Receptors for Drug Design; M. Congreve et al.- Structural Insights into Activation and Allosteric Modulation of G Protein-Coupled Receptors; A.C. Kruse.- Epigenetic Drug Discovery; Chun-wa Chung.- Crystallography and Biopharmaceuticals; R. Pauptit.- Structural Chemistry and Molecular Modeling in the Design of DPP4 Inhibitors; G. Scapin.- Considerations for Structure-Based Drug Design Targeting HIV-1 Reverse Transcriptase; E. Arnold et al.-Protein-Ligand Interactions as the Basis for Drug Action; G. Klebe.- The Protein Data Bank: Overview and Tools for Drug Discovery; H. M. Berman et al.- Small Molecule Crystal Structures in Drug Discovery; C. Groom.- Protein Aggregation and its Prediction; R. Graña-Montes, S.Ventura.- Importance of Protonation States for the Binding of Ligands to Pharmaceutical Targets; A. Podjarny, E. Howard.- Protein-Protein Interactions: Structures and Druggability; D.B. Ascher et al.- Achieving High Quality Ligand Chemistry in Protein-Ligand Crystal Structures for Drug Design; O.S. Smart, G. Bricogne.- Molecular Obesity, Potency and Other Addictions in Drug Discovery; M.M. Hann.- Adventures in Small Molecule Fragment Screening by X-ray Crystallography for Drug Discovery; J.D. Bauman et al.- Structure-Based Drug Design to Perturb Function of a tRNA-Modifying Enzyme by Active Site and Protein-Protein Interface Inhibition; G. Klebe.- Molecular Interaction Analysis for Discovery of Drugs Targeting Enzymes and for Resolving Biological Function; U.H. Danielson.