is Professor of Medicinal Chemistry at Philipps University in Marburg, Germany. He retired in April 2020. He has been teaching pharmaceutical and medicinal chemistry, drug action and drug design for almost 30 years. His research has focused on structure-activity relationships, 3D-QSAR methods, conformational and pharmacophore analysis, docking methods, database analysis, protein crystallography, structure-based drug design, and biophysical characterization of protein-ligand interactions (https://agklebe.pharmazie.uni-marburg.de/?id=&lang=en). The thermodynamic characterization and the involvement of water molecules in the binding process have been a particular focus. A number of well known and worldwide applied computer tools have been developed in his laboratory (CoMSIA, AFMoC, ReLiBase, Cavbase, Drugscore, Mobile). With his research group, he has worked on a signicant number of the drug targets also covered in the book. In total, his group has contributed more than 1600 crystal structures to the publicly available PDB. Together with colleagues at the Bessy synchrotron in Berlin, his group estab­lished a dedicated beamline for fragment-based lead discovery, including many tools for further hit-to-lead optimization. Out of his research group came the start-up company CrystalsFirst (www.crystalsrst.com), which focuses on crystallographic fragment screening using sophisti- cated protein crystal stabilization techniques and combining crystal screening with computational design. Prior to his appointment in Marburg, he taught drug design and crystallography at the University of Heidelberg and worked for more than a decade in an industrial setting in drug discovery at BASF AG in Ludwigshafen, Germany.