Ray Tomlinson

Tomlinson implemented the first system for sending network electronic mail between different computers on ARPANET in 1971. Prior to his work, messages could only be sent between users on the same machine.

He selected the @ sign to separate the user's name from the host computer name in email addresses because it was rarely used in computing at the time and read naturally as 'user at host.' He surveyed the keyboard for a character that would not appear in names.

He worked at BBN Technologies (Bolt, Beranek and Newman), the Cambridge, Massachusetts company that was a key contractor for ARPANET. He worked there for the entirety of his professional career.

Tomlinson later recalled that the first message was a test string of characters, likely something like 'QWERTYUIOP,' sent between two computers sitting side by side in his lab. He did not save the message because he considered it insignificant at the time.