Short answers, pulled from the story.
The first novelization of a film appeared in 1915. This adaptation was of the silent serial Les Vampires, a French crime drama that captivated audiences with its shadowy underworld and masked villains.
Film novelizations reached their commercial zenith in the 1970s. During this period, home video technology had not yet made movies accessible for repeated viewing in the comfort of a living room, creating a desperate demand for written versions of blockbusters like Star Wars, Alien, and Star Trek: The Motion Picture.
A novelization must expand a screenplay of 20,000 to 25,000 words into a novel of at least 60,000 words. Writers often work from an early draft of the screenplay, which means the novel might diverge from the final film and sometimes include deleted scenes that never made it to the screen.
Arthur C. Clarke wrote the novelization of the film 2001: A Space Odyssey. The novel provided exposition that the film deliberately omitted, creating a richer and more complete narrative experience for the reader.
John Gardner and Raymond Benson wrote numerous novelizations for the James Bond franchise after Ian Fleming died. These novelizations often expanded the universe of the franchise, adding new stories and characters that were not present in the films.
The novelization of the film The Micronauts was written by Gordon Williams and published long after the film was never made. The novel has since become a cult classic and exists as a standalone work that was never adapted into a film.