Are the post-Blish Star Trek novelizations canon?
In 1979, Pocket Books (an imprint of Simon & Schuster) began Trek fiction anew with the publication of the novelization of Star Trek: The Motion Picture, written by Gene Roddenberry. So, this counts as canon, right? It’s the novelization of The Motion Picture and it’s written by the Great Bird of the Galaxy himself.
Well… the novelization of The Motion Picture begins with a forward from Kirk himself, in which he makes all sorts of interesting claims. For one thing his middle name is Tiberius. This checks out— that’s canon! (Although the Tiberius thing wasn’t spoken aloud until Star Trek VI: The Undiscovered Country.) But, after Kirk’s intro, we also get a scene where Starfleet sends him signals straight into his brain via something called a “senceiver implant.” Basically, Kirk has a top-secret implant in his brain that lets him receive classified data—just downloaded straight in there, like cyberpunk style. Obviously, there is no reference to this brain implant in other Star Trek canon, which makes the one and only Trek novel written by Gene Roddenberry either a classified document, or mostly non-canon.
If you jump ahead to the David Gerrold novelization of Star Trek: The Next Generation premiere “Encounter at Farpoint,” you’ll discover that Jean-Luc Picard was getting over the death of a girlfriend named “Celeste” right before he took command of the Enterprise. Gerrold was on staff with TNG at the time, and of course, wrote “The Trouble With Tribbles.” But, it’s not like we’ve heard about Celeste in Jean-Luc’s other adventures.
Star Trek books tend not to be holistically canon, but do seem to create canon.
Not only was Kirk’s middle name affirmed by Roddenberry’s TMP novel, but Sulu’s first name, Hikaru, also came from a Star Trek novel. 1981’s The Entropy Effect, written by Vonda N. McIntyre first established Sulu’s first name, which was later made canon on screen in The Undiscovered Country.
Similarly, another famous helm officer in Starfleet — Keyla Demter — got her first name from the Star Trek: Discovery novel Desperate Hours, written by David Mack and published before a single episode of Discovery had even aired. But, the name Keyla stuck, and as long as she’s on DISCO, she owes her first name to a Star Trek novel.