Here is another article on the history of Unix, this time from Ars Technica. One interesting point that I wanted to call out from a mere skim of its contents, it mentions that the famous photo of Ken Thompson and Dennis Ritchie at Bell Labs wasn’t published in Scientific American until Ritchie’s hair was less luxuriant and lighter, and the captions were reversed.
20190829/https://arstechnica.com/gadgets/2019/08/unix-at-50-it-starts-with-a-mainframe-a-gator-and-three-dedicated-researchers/