Simon C. Watkins, Ph.D.: Dr. Watkins is a Professor and Vice Chair of the Cell Biology and Physiology Department at the University of Pittsburgh, Pennsylvania, and holds a secondary appointment as Professor in the Department of Immunology at the same institution. He is also the Founder and Director of the Center for Biologic Imaging at the University of Pittsburgh. Dr. Watkins is an expert in microscopy and imaging and is an Editor for Current Protocols in Cytometry where he is in charge of the chapters on 'Image Cytometry Instrumentation' and 'Cellular and Molecular Imaging'. Claudette M. St. Croix, Ph.D.: Dr. St. Croix is an Assistant Professor in the Department of Environmental and Occupational Health at the University of Pittsburgh, Pennsylvania, and holds a secondary appointment as Assistant Professor in the Cell Biology and Physiology Department at the same institution. She is also Assistant Director of the Center for Biologic Imaging at the University of Pittsburgh. Dr. St Croix's highly inventive applications of advanced imaging technologies have led to numerous invitations to present her work nationally and internationally and to take lead roles in well respected courses such as Quantitative Fluorescence Microscopy (run at Mount Desert Island Biology Laboratory) and at the national Microscopy Society of America annual meeting. She is also an author for Current Protocols in Cytometry.