Ray Tomlinson, the man widely credited with inventing email, has died at the age of 74.
The US computer programmer died of a heart attack on Sunday, according to reports.
Tomlinson is credited with the idea of sending an electronic message from one network to another in 1971. His idea of using the @ symbol as part of an address is now standard.
He sent was is believed to be the first email while working as an engineer at Bolt, Beranek and Newman, a Boston company that worked heavily on an early version of the internet.
Speaking about the first email in 2009, Tomlinson said: "Every time you test you have to generate some sort of message.
"You might drag your fingers across the keyboard or just type the opening phrase from Lincoln's Gettysburg address or something else - so technically the first email is completely forgettable and therefore forgotten."