It’s fairly routine for individual books to get adapted into their own movies and stage plays. Somewhat less common, though still far from unusual, is for a writer to take two or more books from a certain author, or from a certain book series, and adapt them into a single (screen)play. An example would be Disney’s The Black Cauldron, which is adapted from the first two novels in Lloyd Alexander’s Chronicles of Prydain series.
What is really rare, I think, is for a writer to take several completely unrelated books (i.e., not written by the same author, not part of the same series, and not set in the same fictional universe) and spin them into a movie or play with a single, coherent narrative. The only example of this that I’m aware of and that I’ve seen is The Flight of Dragons, a 1982 Rankin–Bass film that somehow melds Gordon R. Dickson’s novel The Dragon and George with the speculative evolution book The Flight of Dragons by Peter Dickinson.
Some Googling leads me to believe that Tales from Earthsea may be another example, but I’m not sure as I haven’t seen it myself and am not familiar with the source material. According to Wikipedia, the movie “is based on a combination of plot and character elements from the first four books of Ursula K. Le Guin’s Earthsea series (A Wizard of Earthsea, The Tombs of Atuan, The Farthest Shore, and Tehanu), as well as the manga The Journey of Shuna by Hayao Miyazaki”. Can anyone verify that this is a genuine example of the sort of film I’m talking about?
Can anyone name any other non-anthological films or plays, or other dramatic works, that adapt two or more completely independent books?