John Dunne's first assignment as a field applications specialist for Coulter in 1983 was to walk company founder Wallace H. Coulter through a FASEB meeting, translating some of the biology to the renowned electrical engineer who discovered the Coulter principle. "Learning what an engineer cares about when listening to biologists changed how I think about problems," says Dunne, now associate scientific director at BD Biosciences. On page 20, he writes about the work of the group he leads, applying flow cytometry to the mapping of immunological responses.