Electronic mail is generally known as email or e-mail and it is a way of exchanging digital messages from one computer network to another.

Email was invented by Raymond Samuel Tomlinson in late 1971s on ARPANET network. He was born in 1941 at Amsterdam, New York and completed his graduation from Rensselear Polytechnic Institute. Ray Tomlinson is a computer engineer by profession. The first email sent by Tomlison was between two computers placed side by side. These two computers were connected using the ARPANET network.

Originally the transmission of email from one computer to another computer was done directly. Both computers had to be online at the same time for instant messaging. Present day computers use email servers and these email servers forward, accept, store and deliver messages. Users need not be online simultaneously and have to be connected only for a brief period of time to the email server, for the duration it takes for sending or receiving messages.

 

source: http://www.letusfindout.com/who-invented-email/