The screenwriter took liberties with the original story line of the novel, but the basic story is portrayed well in the movie. But I have to say, it isn't even as detailed as a "Cliff Notes" version of the novel. I'm a fan of the novel, so I didn't like how Phoebe's "Steve Jobs" like brother was not included in the screenplay. I also thought that it was important to establish that Wolf was from the same high school as Phoebe and her sister. The character of Wolf in the film was from England. The idea of two native San Franciscans escaping to Europe during the Vietnam War Era was critical to the story, I felt. Wolf can't go back to a world where he grew up, San Francisco and UC Berkeley, after the death of Faith. He's stuck, and he can't face Phoebe and her mother. Wolf merely living a few hours away from where he grew up doesn't portray the sense of self-imposed isolation an American might feel living in Germany, where he survives on the German he studied merely for his foreign language requirement at UCB. An Englishman living in Paris (Wolf in the movie), where many people speak English, just doesn't portray the sense of exile Wolf must feel.
But the movie is fine if you don't compare it to the book. Like the book, the story takes place in the 1970s, but it might as well have taken place when the movie was made, the 1990s. There's beautiful scenery, but the story is too condensed, and the surprise ending doesn't have the same long build-up as in the novel. In the end, the story was wonderful for a full length novel, but does not seem to work as well for a movie.