Ray Tomlinson sent the first network email in 1971.
Tomlinson was working on ARPANET systems at Bolt, Beranek and Newman when he adapted an existing local electronic-mail program so messages could travel between separate computers. His work made it possible to identify a recipient by both a user name and a host computer.
The first message was a test sent between two computers placed side by side and connected through ARPANET. Tomlinson later said the exact text was not memorable, although it is often described as something like a row of keyboard characters.
Tomlinson also chose the @ symbol to separate the user from the destination host. That symbol became a defining part of email addresses. Network email in 1971 should not be confused with earlier local mail programs, which could exchange messages only among users of the same computer.