Born on September 9, 1941, Dennis Ritchie was one of the developers of the Unix family of operating systems, which includes Linux and macOS. The massively influential C programming language was his brainchild. He also co-authored the book detailing how the language works in its original form, commonly called K&R C. He’s the “R” in K&R.
Ritchie’s legacy (he died in October 2011) can be accessed anywhere online. Very nearly everything on the Internet was written in C, or some derivative of it. C#, C++, Python and Java are all derivatives of it.
More on Ritchie:
Dennis Ritchie Home Page
The Shoulders Steve Jobs Stood On | Wired