The basic idea of the book and movie are similar. An extremely rich man named John Hammond gets an island off the shore of Costa Rica. He has scientists clone dinosaurs. Things go wrong, so he has some consultants come see the island to see if it is safe. These consultants include Dr. Alan Grant (paleontologist), Dr. Ellie Sattler (paleobontanist), and Dr. Ian Malcom (mathmetician). He also invites his grandkids, Tim and Lex Murphy. The book and movie both center around the events that happen to these people while they are on the island.
Most of the characters from the book also make it to the big screen in the movie. Dr. Alan Grant and Dr. Ellie Sattler are still in the movie. They are still scientists. The same thing goes for Dr. Ian Malcolm. Denis Nedry is still the annoying computer technician. Dr. Harding is still the vet for the dinosaurs. Muldoon is still the game warden. John Arnold is still the egineer. Though Ed Regis, Donald Gennaro, and Dr. Wu play a much smaller role in the movie than in the book, they are still present. All the mentioned characters come across differently in the movie than in the book, but they at least are still included.