This detailed book explores the numerous applications of the yeast two-hybrid (Y2H) system, one of the most commonly used methods to detect protein-protein interactions. Beginning with an overview, the volume then continues by elucidating different methodologies to detect protein-protein interactions in yeast nucleus, membrane, cytoplasm, and bacteria, computational analyses of protein interaction networks, technical variations in yeast one-hybrid (Y1H) systems together with classical and more elaborated yeast methods to detect protein-DNA interactions, as well as protocols to analyze ternary protein interactions and RNA-protein and ligand-protein interactions. The book concludes with a section on methods in plant and mammalian cells that can be used to identify novel protein-protein and protein-DNA interactions and test (qualitatively and/or quantitatively) those observed in yeast. Written for the highly successful Methods in Molecular Biology series, chapters include the kind of detail and key implementation advice that leads to excellent results in the lab. Authoritative and practical, Two-Hybrid Systems: Methods and Protocols serves as an ideal guide to the uses of this exceedingly valuable technique.