Book excerpt: 1. G protein-coupled receptors in the human genome -- 2. Why G protein-coupled receptors databases are needed -- 3. A novel drug screening assay for G protein-coupled receptors -- 4. Importance of GPCR dimerization for function : the case of the class C GPCRs -- 5. Molecular mechanisms of GPCR activation -- 6. Allosteric properties and regulation of G protein-coupled receptors -- 7. Chemogenomics approaches to ligand design -- 8. Strategies for the design of pGPCR-targeted libraries -- 9. Ligand-based rational design : virtual screening -- 10. 3-D structure of G protein-coupled receptors --11. 7TM models in structure-based drug design -- 12. Receptor-based rational design : virtual screening.