This detailed volume assembles comprehensive protocols to assist with the study of structural, molecular, cell biological, and in vivo facets of GPCRs, and to enable the development of experimental tools for screening novel GPCR drugs. Sections explore the tweaking of ligands, bioluminescence and FRET approaches, specific GPCR signaling properties, as well as visualization of subcellular compartmentalization. Written for the highly successful Methods in Molecular Biology series, chapters include introductions to their respective topics, lists of the necessary materials and reagents, step-by-step, readily reproducible laboratory protocols, and tips on troubleshooting and avoiding known pitfalls.