Claude Shannon
loreprogrammingnetworking
The author of the 1948 paper that founded information theory, and, a decade earlier, of the thesis showing that Boolean algebra describes switching circuits.
Two contributions, either of which would have been a career. The 1937 thesis made digital logic a design discipline rather than a craft. The 1948 paper defined information as a measurable quantity and gave the ceiling on what any channel can carry given its bandwidth and noise - which is why capacity planning is arithmetic rather than opinion, and why every claim about a faster link eventually meets a number Shannon wrote down. Compression, error correction and modulation are all consequences.
Also known as: shannon, information theory