Novelizations and (less commonly) comic-adaptations of films filled this role generally, before home video releases were common & affordable. The Star Wars nove

Novelizations and (less commonly) comic-adaptations of films filled this role generally, before home video releases were common & affordable. The Star Wars novelization, for example, didn't sell well because it was a great book, but because most kids couldn't re-watch the movie every single day like they could when the VHS releases came out, so they'd instead read a $1.25 mass-market paperback until it fell apart. They were chiefly memory-refreshers for the actual film. There was even a brief span of time in which audio versions (often of the film itself, not necessarily of the novelization, so, not exactly an "audio book") helped filled this role for some films, because audio cassettes & stereos/walkmans were more widely available & affordable than video decks. Maybe I'm imagining it, but I wanna say there were things like re-cap books for seasons of shows like The X-Files, even, because home-video copies of entire shows were prohibitively expensive for all but the craziest fans. That's also part of what coffee-table type books about shows & movies were for—lore & encyclopedic content mixed with stills and what were effectively plot and episode summaries.