Flow cytometry is a powerful technique for the analysis of multiple parameters of individual cells within heterogeneous populations. Flow cytometers are used in a broad range of applications including immunophenotyping, fluorescent protein detection, rare event analysis, live/dead cell testing, stem cell characterization, and more. As an introduction to fluorescence, this presentation covers the following topics: the principle of flow cytometry; components of a flow cytometer; basics of fluorescence and how to interpret a dye excitation/emission spectrum; how data is displayed; compensation principles and techniques; and the types of controls recommended. This webinar is useful for new and practiced cytometer users interested in learning the general concepts and principles behind flow cytometry.