Robert Hawley, professor of Anatomy and Cell Biology, co-edited and contributed a chapter to Flow Cytometry Protocols, Fifth Edition, with Teresa Hawley, the inaugural and former director of the GW Flow Cytometry Core Facility. This new edition includes the latest developments in conventional, full spectrum and imaging flow cytometry, mass cytometry, and imaging mass cytometry. It is dedicated to the memory of Howard Shapiro, MD, PC, a luminary in the flow cytometry field. Dr. Shapiro's introductory chapter to the fourth edition recounting the landmark discoveries leading to the birth of flow cytometry was reproduced as a tribute to him.