How the symbol @ came to be used in Email Addresses?

Since medieval times business man-hour used the symbol @ as an abbreviation for 'at' or 'each' - for example 'lac @ 1 pence a metre'. This is why it is included on the typewriters and subsequently, computer keyboards.

In 1972, American software engineer Ray Tomlinson, working for Computer Bolt, Beranek and Nenman, devised the first e-mail program. In order for it to operated he needed a symbol to separate the user name from machine details in e-addresses. The character had to be one that would never be found in someone name.