G protein-coupled receptors (GPCRs) are one of the most important target classes in pharmacology and are the target of many blockbuster drugs. Yet only with the recent elucidation of the rhodopsin structure have these receptors become amenable to a rational drug design.Based on recent examples from academia and the pharmaceutical industry, this book demonstrates how to apply the whole range of bioinformatics, chemoinformatics and molecular modeling tools to the rational design of novel drugs targeting GPCRs.