From the Los Angeles Times:
"I don't think all of us wanted to go through all the writers we did," says David Kirschner, one of the producers on the film. "The first script I worked on and was closely involved with was by Mike Werb ('Face/Off')," he says. "It was pretty good. ... Pat Proft did a [live-action] draft on this that had a lot of really funny, funny stuff, but in the end, what we really wanted was the special relationship between this man and this little monkey. As simple as those pages are, and they look like a rather short children's book, it was really difficult to capture the innocence of that."In all, apparently, it took millions of dollars, several directors, nine studios and FORTY-TWO scripts to finally get one film.