Personal history of Tom Van Vleck. The history of electronic mail and instant messaging, written in 1965 for MIT Computation Center's CTSS timesharing system and later re-implemented on Multics.

Computer mail and messaging have probably been independently invented many times. I do not know who first invented these applications; I haven’t found any documented versions of computer mail that precede the one I helped create in 1965. This note describes my knowledge of the history of electronic mail and instant messaging.