The book is quite a bit different from the movie, with a lot of things that weren't in the film and quite a bit of profanity. That said, it was also pretty funny, and Forrest comes across as being smarter than most people around him. It's a good story, and I like both the original book and the film interpretation.
"Oh, you can’t help that," said the Cat: "we’re all mad here. I’m mad. You’re mad." "How do you know I’m mad?" said Alice. "You must be," said the Cat, "or you wouldn’t have come here.”