Though its exact history is murky, email (e-mail) began as a way for users on time-sharing mainframe computers to communicate. Among the first systems to have an email facility were System Development Corporation of Santa Monica's programming for the AN/FSQ-32 (Q32) built by IBM for the United States Air Force Strategic Air Command (SAC), and MIT's Compatible Time-Sharing System (CTSS). The authors of the first email program for CTSS were American software engineer Tom Van Vleck and American computer scientist Noel Morris. The two men created the program in the summer of 1965.
"A proposed CTSS MAIL command was described in an undated Programming Staff Note 39 by Louis Pouzin, Glenda Schroeder, and Pat Crisman. Numerical sequence places the note in either Dec 64 or Jan 65. PSN 39 proposed a facility that would allow any CTSS user to send a message to any other. The proposed uses were communication from "the system" to users informing them that files had been backed up, and communication to the authors of commands with criticisms, and communication from command authors to the CTSS manual editor.
"I was a new member of the MIT programming staff in spring 1965. When I read the PSN document about the proposed CTSS MAIL command, I asked "where is it?" and was told there was nobody available to write it. My colleague Noel Morris and I wrote a version of MAIL for CTSS in the summer of 1965. Noel was the one who saw how to use the features of the new CTSS file system to send the messages, and I wrote the actual code that interfaced with the user. The CTSS manual writeup and the source code of MAIL are available online. (We made a few changes from the proposal during the course of implementation: e.g. to read one's mail, users just used the PRINT command instead of a special argument to MAIL.)
"The idea of sending "letters' using CTSS was resisted by management, as a waste of resources. However, CTSS Operations did need a faclility to inform users when a request to retrieve a file from tape had been completed, and we proposed MAIL as a solution for this need. (Users who had lost a file due to system or user error, or had it deleted for inactivity, had to submit a request form to Operations, who ran the RETRIEVE program to reload them from tape.) Since the blue 7094 installation in Building 26 had no CTSS terminal available for the operators, one proposal for sending such messages was to invoke MAIL from the 7094 console switches, inputting a code followed by the problem number and programmer number in BCD. I argued that this was much too complex and error prone, and that a facility that let any user send arbitrary messages to any other would have more general uses, which we would discover after it was implemented" (http://www.multicians.org/thvv/mail-history.html, accessed 06-20-2011).
♦ On June 19, 2011 writer and filmmaker Errol Morris published a series of five illustrated articles in The New York Times concerning the roles of his brother Noel and Tom Van Vleck in the invention of email. The first of these was entitled "Did My Brother Invent E-Mail with Tom Van Vleck? (Part One)". The articles, in an usual dialog form, captured some of the experience of programming time-sharing mainframes, and what it was like to send and receive emails at this early date.