"The Making of Star Trek" by Stephen Whitfield, published 1968 roughly between seasons 2 and 3 of the original series. This volume has two sections of monochrome photos, most being publicity shots or behind the scenes type images. It also contains a few pages of conceptual illustrations, earlier designs that eveolved into thew Enterprise, layouts of Desilu's Stage 9 that conatined the standing sets. It also has early drafts of "The Cage" when the alien telepaths were described as crab-like. This paperback is considered one of the oldest "reference" books for Trek, and the only one for several years.
"The Making of 'The Trouble with Tribbles'", written by the episode's author David Gerrold, who also wrote "The world of Star Trek". This early 70s publication is the author's personal account, describing the development of a single episode from his initial idea to its debute broadcast. He details drafting several premises before choosing "...Tribbles" as the most practical. (At least one of these, "The Protracted Man" has finally been realized for the "fan made" series "Star Trek Phase Two".) He recounts visiting the studio to get a better feel of the characters as he revises his drafts. He also mentions having a "scare" when he wonders if he may have imitated Heinlein a bit too closely. It's a personal tome that let's one peek into the mind of the author as he grows as a professional television writer.
These two books and the one you mentioned were "treasures" during the relatively "dry years" of the 70s until the first motion picture debuted.