Regex Legends: The People Behind the Magic
blog.stevenlevithan.com
blog.stevenlevithan.com
VM Glushkov should be on the list. His NFA formulation both predates Thompson's and has significant advantages for efficient implementation.
I read Friedl's book years ago and I found it incredibly useful.
Whatever damage Friedl did to my understanding of an NFA has been de minimus in comparison to how that book improved my skills. I wish more of my coworkers had encountered Friedl's book.
Understanding the history of how we got here is crucial.