This fourth edition volume expands on the previous editions by presenting readers with new and emerging methodologies in cytometry. The chapters in this book cover various topics such as quantifying surface and intracellular protein biomarkers, intracellular cytokine staining, apoptosis analysis, cell cycle analysis, tracking cell proliferation, and monitoring protein-protein interactions using FRET. Some developing methodologies that explored are mass cytometry, vesicle flow cytometry, time-resolved flow cytometry, and real-time label-free deformability cytometry. Written in the highly successful Methods in Molecular Biology series format, 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. Cutting-edge and comprehensive, Flow Cytometry Protocols, Fourth Edition researchers and scientists who are interested in continuing or expanding their knowledge of flow cytometry.