I had Whitfield's book, Gerrold's Tribbles and World of, all the Foto-novels, the Concordance, Franz Joseph's Tech Manual, at least one of Geoffrey Mandel's books. I was audio taping the episodes during the 70s, and would take them and the Foto-Novels to work (underground, alone, no windows or radio), and follow along.
[Gerrold] recounts visiting the studio to get a better feel of the characters as he revises his drafts.
Is that where he mentions Shatner coming over to see what he's doing? And Gerrold tells him, "I'm writing a script where you lose your voice in the teaser and don't get it back until the tag." Which didn't go over well. And pretty much does happen in The Tholian Web.