I grew up on TNG and the original movies with some viewing of DS9 and Voyager, I only saw a few Original Series episodes that my friends had on video. I did not get to see the entire series, which was never on antenna or basic cable TV where I lived, until much later.
I haven't read the Blish novelizations (novelettizations, really, looking at the length), and never read any TV tie-in print fiction, but Wikipedia has some interesting information on them
Blish was known to have expressed an extreme dislike for tie-in fiction, however he accepted the commission from Bantam Books to novelize episodes of Star Trek, at $2,000 per volume.:21, 324 He later stated his financial stability stemmed from the publication of the novelizations. Which likely included the commission for Spock Must Die! (1970), which earned him a $3,000 advance (equivalent to $20,916 in 2019).:358
Prior to his relocation to the United Kingdom in 1969, Blish had not seen the NBC broadcasts of Star Trek. Nor was he involved in the production of the series in any capacity. His only sources for the adaptations were the draft teleplays sent to him by Desilu. Adaptations published after 1970 aligned more with the narrative tone and pacing from the television series, indicating Blish had seen some episodes. Mostly likely via broadcasts by the BBC, which began the summer of 1969.
Blish was credited exclusively for eleven volumes, although it was later acknowledged that volumes published after Star Trek 6 (1972) were written in collaboration with his wife J. A. Lawrence and her mother, Muriel Lawrence, who was also Blish's assistant. Blish commented favorably about the series in each of his "Author's Notes", however, Josephine Saxton said Blish was "so affected to despise" Star Trek that he did not write any of Star Trek 10 (1974).:25 Blish's personal feelings regarding the merit of Star Trek were expressed by the pun "an enterprise so well conceived" in the "Author's Note" of Spock Must Die!.:25
Bantam editor, Frederik Pohl, was unaware of the Lawrences' contributions until sometime in 1973.:8–9 Star Trek 12 (1977), published after Blish's death in 1975, was co-credited to J. A. Lawrence.
Adaptations of episodes involving the character Harry Mudd were reserved by Blish for inclusion in an original novel, possibly a follow up to Spock Must Die! However, it is unknown if the book was ever realized. The novelizations of "Mudd's Women" and "I, Mudd" were collected as Mudd's Angels (1978),[a] which included an original novella by Lawrence: The Business, as Usual, During Altercations. Lawrence confirmed the Mudd novelizations were written by Blish, and not by her.
I've read a bunch of Blish stories that I liked but I really do not like his supposed masterpiece, the novel A Case of Conscience, is one of my least favorite classic science fiction novels. If people want to like it despite its faults because as a made up story in entertains them then fine, it's readable enough, but when people praise it as science fiction that takes religion seriously they are being ridiculous. And really I think alot of it is kind of dumb even if you ignore the central conceits.