Obviously there are countless books adapted into movies, The Da Vinci Code, Harry Potter, Lord Of The Rings etc.. but are there any movies that have been succesfully adapted to books? If not, do you think it would be possible?
Yes. There's no movies I can refer to, but it can be done. Before one shoots a movie, a manuscript is written, with stage details, actions, descriptions of the scenes, a plot, the subplots, everything. Change its format and add some words. Bam, you've got a book.
A lot of video games have been adapted to books (just look at all of the Blizzard novels). As well as even card games (Magic the Gathering being the most popular). So yes, I think their could easily be movies made into books. Although, none come to mind straight away.
Arthur C. Clarke's novelization of 2001: A Space Odyssey was written after the movie. So was Isaac Asimov's Fantastic Voyage. By the way, the word you want is adaptation.
I love reading video game adaptations for games I don't care to play (Resident Evil series comes to mind). As far as movies go, I think in only the rarest of occasions (as Cogito pointed out) are movies adapted into books. I know the first Spider-man movie had a novelization that came out 2 months before the movie. I read the whole thing, cover to cover, in one night and spoiled the whole experience. Never doing that again that's for sure.
Terry Brooks' Hook and Star Wars Episode One: The Phantom Menace are a couple I know about off the top of my head. Not sure on the timing of either; I'm fairly certain the books came out a few months before the films (to help with marketing and advertising the films), but he started writing them after they had started filming both projects (i.e., they contacted him to make adaptations of the films). Not sure what else to say about it. It definitely happens, and I'm sure this kind of thing is done fairly often. I enjoyed the Star Wars episode one book more than the movie, but I never read Hook. Brooks has said working on the Hook project was one of his worst experiences as a writer, but he has said he liked doing the Star Wars book. Personally, I could never see myself writing the book adaptation of a film. I like to go running and playing in my worlds, but I tend to feel a bit too creatively limited when working with someone else's world. And then you also have to worry about how cooperative the folks wanting you to write the book will be. It's been years since I've read about Brooks talking on the above mentioned projects, but one of the reasons I think he found Hook as a bad experience is because they limited his access to the studios, sets, actors, and so on, and that in turn limited his research. I'm actually not sure if they provided him with the full script used for the film. George Lucas, on the other hand, opened everything up to him, and he's said the two experiences were like night and day in comparison. Like I said, it's been years, almost a decade actually, since I've read about this stuff, so my facts may be slightly off. It's all served from memory now, though I think he talks about it in his book Sometimes the Magic Works: Lessons from a Writing Life.
...no, none have been done 'successfully' if by that you mean done to critical acclaim, though there are many adaptations out there in print... in addition to the ones mentioned, there's an entire star wars series, along with star trek, battlestar, etc. ... if you mean only that rabid fans of the movies buy a sufficient number of books to make it worth the publisher's and producer's time/money/effort, then i suppose you can say the answer is yes... ...and i seriously doubt that any screenplay can ever be 'successfully' adapted in the literary sense... unfortunately, while some great novels have been turned into excellent and even prize-winning movies, it takes a great writer to write a great novel and i doubt any of that caliber would bother to take on the tiresome task of rehashing someone else's work...
Maybe not really movie to book, but Wolf's Rain was an anime first, and then made into a manga (with a lot of changes to my surprise) and I believe both are critically acclaimed.
I am not sure if you are just speaking of direct adaptations, or anything based of the world. If you are strictly speaking of direct adaptations then I would agree. But if you are talking about anything based on the world, I would disagree just on the "Han Solo Trilogy" alone. They are awesome books.