Mark Cheetham started in Flow Cytometry in 1984 as a key operator of an early research Flow Cytometer/ Cell Sorter within the Paediatric Research Unit at Guy's Hospital London. The position involved setup, calibration and maintenance of the system for a group of users, as well as a research project into the Ontogeny of Human T Cells in the Neonate. He then joined Coulter Electronics in 1987 as a Flow Cytometry Applications Specialist. Working the UK and Nordic countries, Mark provided both pre sales and post sales support for Coulter Flow Cytometry Products. In the late 90's just prior to the merger with Beckman Instruments, Mark became the UK Flow Cytometry Product Manager, retaining some of his support responsibilities but also launching new products and running different Marketing activities. Mark then moved to Miami in the US to take up a position as US Flow Cytometry Product Manager for Beckman Coulter in 2003 and returning back to the UK in 2007 again as UK Flow Cytometry Product Manager, Beckman Coulter. Mark's expertise is developing Flow Cytometry techniques and implementing Flow Cytometry in to new applications in fields from Marine biology to Immunology.