Donald Gennaro - The head of In Gen's account with the law firm Cowain, Swain and Ross.Gennaro is nervous about the progress of Jurassic Park and has heard rumors of animals getting off the island.Irritated that Hammond refuses give him more firepower to handle large species like the tyrannosaurus, Muldoon is more concerned about the raptors, which are totally unmanageable. John Arnold - The head engineer at Jurassic Park, who previously worked with missiles and at amusement parks.
Grant is athletic and down-to-earth, and takes pride in not being a stuffy academic like many of his colleagues.
Although certain characters seem to resent the presence of Hammond's grandchildren, Grant likes children and is quickly drawn to Tim in particular.
Nedry is smart, fat, and surly, and, in his dealings with Biosyn, represents the novel's lone antagonist human character.
His computer hacking is responsible for all the problems that send Jurassic Park into turmoil.
Robert Muldoon - The park's game warden, formerly a big-game hunter and zoo consultant.