While working at the RAND Corporation in the early Sixties, Baran outlined a method for dissembling information into "message blocks" in order to move them through a network, reassembling them at the end point. This method has come to be known as "packet switching."
The term "packet switching" was coined by Donald Davies, a UK researcher also working on the same process.
To understand the development of package switching as Baran outlined it, it is important to remember that its creation took place at the height of the Cold War between the U.S. and its allies and the Soviet Union and its allies. The innovation was security-based. By separating a message into parts, sending the parts by redundant routes, and only putting them back into coherent form at the end, it would make them much less likely to be intercepted. It would also ensure delivery even if individual nodes in the network were compromised or destroyed.
He outlined his full proposal in what the Computer History Museum described as "a 13-volume set of reports defining in detail an all digital nationally distributed network for digital voice and data."
Baran was born in Poland, emigrated to the U.S. and took a degree in electrical engineering at Drexel University in Philadelphia. Baran worked on the Univac at the Eckert-Mauchly Computer Company and for Hughes Aircraft in Los Angeles while earning a Masters in Engineering at UCLA. At that point he joined RAND.
It wasn't until 1969 that anyone actually built a network like the one Baran described. That was the U.S. Department of Defense's Advanced Research Projects Agency Network, or Arpanet. The ARPANET was eventually replaced by the National Science Foundation Network, which grew into what we now know as the Internet.
Baran was preceded in death by his wife Evelyn, who passed away in 2007, and is survived by his son, David, three grandchildren and his companion Ruth Rothman.
*That was Al Gore, of course