The chances are you've never heard of him, but without his pioneering work in the 1960s, you wouldn't be reading this web page, because there wouldn't be a web for you to read it on.
His name is Paul Baran, and he died March 26, aged 84. Baran, a Polish-born engineer at the RAND corporation, invented one of the most fundamental aspects of internet technology, the concept that later became known as "packet switching".
Put simply, packet switching is the way data is chopped up into smaller chunks, and each chunk is sent across a distributed network to end up at its destination.
The chunks, or packets, might not all take the same route. The whole point is that there are many different routes available to them. Each packet has something called a header a summary of metadata, information about the packet and its contents.
As the packets arrive at their destination, the packet headers tell the computer there how to re-assemble them in the right order.
Baran shares some of the credit for packet switching with researchers Donald Davies and Leonard Kleinrock, who were working independently along similar lines; before they came up with the idea, information had to go from point A to point B using what's called circuit switching. (Think of old footage of manual telephone exchanges, where operators plugged wires to connect one circuit with another.) With packet switching, a single circuit could be used more efficiently, to send more data between more people.
Baran's pioneering work in this field was a direct precursor to the creation of the government-sponsored network Arpanet, which itself was one of the first building blocks of the internet as we know it today.
A version of this text originally appeared on TIME.com on March 28, 2011.