Facing the wall in computationally based approaches to drug discovery -- The changing landscape in drug discovery -- Purine nucleoside phosphorylase -- Application and limitations of X-ray crystallographic data in structure-guided ligand and drug design -- Dealing with bound waters in a site : do they leave or stay? -- Knowledge-based methods in structure-based design -- Combating drug resistance : identifying resilient molecular targets and robust drugs -- Docking algorithms and scoring functions : state-of-the-art and current limitations -- Application of docking methods to structure-based drug design -- Strength in flexibility : modeling side-chain conformational change in docking and screening -- Avoiding the rigid receptor : side-chain rotamers -- Computational prediction of aqueous solubility, oral bioavailability, P450 activity and hERG channel blockade -- Shadows on screens -- Iterative docking strategies for virtual ligand screening -- Challenges and progresses in calculations of binding free energies : what does it take to quantify electrostatic contributions to protein-ligand interactions? -- Discovery and extrapolation of fragment structures towards drug design -- A link means a lot : disulfide tethering in structure-based drug design -- The impact of protein kinase structures on drug discovery.