As Denton Gentry said of Kernighan and Ritchie's book on the C programming language, "Its terseness was a continuing theme in the work of Dennis Ritchie; it says exactly what needs to be said, and nothing more."
Unix and C were written for mainframes decades ago, when the idea of talking to a computer with something other than punched cards was still reasonably novel. And yet, the inventors of Unix created something that is inescapably foundational in computing today, from iDevices and Android phones (and even ski goggles!) to the DoD's largest supercomputers -- because they got the programming interface right, or at least right enough and simple enough; pointers and file-open and fork. And C is even more broadly foundational than that.
Let me restate that, to avoid understating it. If you have any modern device that does more than the very barest bit of digital processing, there are pieces of that system -- probably the core, critical pieces -- that are written using pieces of programming interface that Dennis Ritchie and a small number of colleagues designed.
Crossposted from Dreamwidth (original here), with comments. Comment here or there.