No, Michael Crichton did not write a book before this movie was made, and it shows.
This movie was all about action, and there wasn't much science stuff involved. The story is pretty simple, and there were some wacky part in this movie.
The raptors were radically changed; now they have feathers pointing out of their heads, there heads were a bit longer, and some part of them near their heads is PURPLE AND BLUE. I AM NOT JOKING. It looks dumb, and takes away from the movie. When I saw it, I'm just like, "What the crap is that??" Weird.
Another thing, the second movie was on Isla Sorna, and there was no sightings or mention of a Spinosaurus. Don't get me wrong, the Spinosaurus is my fave dinosaur in the JP series. That just seemed weird.
All in all, a great movie. A ton of fun, and it rocks. Buy the whole JP series, trust me, you'll like every single one!!!!