There is a big discrepancy between screenplays and book manuscripts. Many of us who have written a book and then contemplated turning it into a screenplay have realized this, and I don't know about you, but it totally scared me off. There's a lot in a screenplay that you don't have to spell out in a book.
Fortunately, there is also much in a book that can be left out in a movie, and still get the main plot across. One such book I came across this past weekend. It had been made into a movie that I totally enjoyed, so I thought the book would be a great read.
No such luck. Not only was there more to the basic story than before supposed, but it had the kind of language I wouldn't let my children read, and conversed about sex in entirely too free and casual a way. Definitely not for me. For once, it was a much-better-than-the-book-movie.
Have you ever read a book and thought it would make a great movie? I know there have been many like that. My kids wish that Mr. Heimberdinger would make a movie out of the first Tennis Shoes Among the Nephites. He did an excellent job with Passage to Zarahemla -- but then, he says himself that it was originally written as a screenplay.
I think those that write for movies or television have a whole different set of rules and problems than that which face the novel writer. Personally, I'm not ready to jump into that boat -- I'd probably sink faster than I could bail.
Fortunately there are many out there who are talented enough for that, so I can stick with writing stories. Now if only I could get the time carved out and the fingers going...