It began in a colleague’s lab, located less than a mile from the house where I grew up. The space where that lab is now located had been a deep quarry and my favorite swimming hole. Retuning in my thirties, it once again became a favored hangout, now with the quarry filled in and built upon it the research headquarters of SmithKline. In that lab, Paul K. Horan (PKH) and Kathy Muirhead, introduced me to flow cytometry, a technique we all thought had potential clinical applications. Honestly though, this gave me the opportunity to get out of the Philly heat and play with lasers, computers, and fluorescent colors. With the help of Bob Frescatore and Tom Schmitt we implemented a single-color immunophenotyping assay, the first offered by a national clinical laboratory. Originally intended for use to characterize leukemias and lymphomas, we soon found ourselves swamped with requests for CD4 counts as the AIDS epidemic established itself throughout the world. We went on to implement assays assessing DNA cell cycle, detection of platelet bound antibodies, and measurements of light chain clonal excess. Ten years later, while working at the NIH using the PKH family of dyes to track tumor infiltrating lymphocytes, Jim Yang and I stumbled across what is now known as the dye dilution assay, widely used for monitoring cell proliferation. At Dartmouth College in the 90’s, Alice Givan and I went on to use flow cytometry and confocal microscopy to experimentally-prove that dendritic cells could process and cross-present exogeneous antigens via MHC class I, a mechanism an NIH reviewer called ‘lunacy’. Fast forward to 20 years at Roswell Park, and the development of several MRD assays including a 27-color, single tube, spectral panel with Kah Teong Soh and Joe Tario and it is stunning how far the technology has progressed. Every year, new and increasingly sophisticated applications for flow cytometry are published. As Betsy Ohlsson-Wilhelm, a current colleague will present here, we will soon be labelling cells with 50, even 100 fluorochromes. We all enjoy an incredibly dynamic field that has provided me with opportunities to answer intellectually challenging questions impacting lives across the globe, to interact and train hundreds of students, while travelling the world and developing lifelong friendships.