Moonraker, the novel, is significantly different from the film.
That could be said about all the Bond films.
After a brief picture of the everyday work of the 00 secret agent, Bond is invited to a special, off-the-books job by M. Hugo Drax, hideously scarred multimillionare, pride of England, has been cheating at bridge at an exclusive london club, Blades. Bond beats him at his own game, with the help of Scarne's book.
The next day Bond is formally assigned to replace the freshly murdered security officer at Drax's great project, the Moonraker. The Moonraker is a ballistic missile that can drop a nuclear bomb on any European capital, and sabotage is feared.
Drax's crew is all expatriate german engineers with shaved heads and extravagant moustaches. Bond discovers a few irregularities, but nothing conclusive until someone tries to drop half of the white cliffs of dover on him and Gala Brand. She discovers that the Moonraker, scheduled for a test flight into the North Sea with an instrument package, is actually targeted at downtown London with a nuclear warhead.
She is captured by Drax, and in the ensuing chase, so is Bond (a chase that includes the destruction of his beloved Bentley). The next chapter is one of the most beautiful now-that-I've-got-you-where-I-want-you-I'm-going-to-brag-and-tell-you-my-whole-plan scenes I've ever read. Drax is actually an unrepentant Nazi, a commando who has done all this for vengance against England.
Bond and the girl escape and reprogram the missile to go to its original test target, where Drax and his crew have gone in a Russian submarine to gloat.
So much for the villain.
Bond, looking forward to a month in southern France with Gala, learns she is engaged, and the book ends with Bond alone and a little more bitter, a little colder, a shade less human. Far superior to the nookie-in-space joke that ends the movie.