Ray Tomlinson invented email.

In 1971, he was working at computer company Bolt, Beranek, & Newman in Cambridge, Ma., and he decided to see if he could get two of the machines in his lab to exchange messages.

Tomlinson began searching for a character to separate a name from a place so that computers sending messages wouldn’t confuse the two. Now he is credited with being the first to launch the @ sign into cyberspace.

“I was lucky. I was writing this code and had to find some character to separate the name from the place. I looked at the keyboard and when you get right down to it, there aren’t a lot of options. I thought of the @ sign in just a few seconds,” says Tomlinson, who in 1965 earned a master’s from MIT in electrical engineering.

He says the idea didn’t make him rich, but it did make him happy. Every day millions of emails pop up on screens across the world and every one has the @ sign.

A low-key guy who downplays his accomplishment, Tomlinson says: “It’s an interesting thing to have done.”