Grant is the primary protagonist of Jurassic Park: much of the novel is written from his perspective, and most of the scientific background information, especially about dinosaurs, comes from his thoughts, recollections, and analysis. Grant is a professor of paleontology at the University of Denver who became famous in the eighties for his field research on fossilized dinosaur nests in Montana. Despite his preeminence in the field of paleontology, Grant sees himself as quite different from his stodgy, academic colleagues. Rather, Grant is an easy-going "average guy" who does not mind getting his hands dirty. In the face of the crisis that occurs at the park, Grant is the perfect levelheaded, unbiased protagonist. Throughout a series of deadly dinosaur attacks, the only time he ever loses his composure is when he yells at Gennaro to own up to his responsibility and help him find the raptor nest.
Although several characters are annoyed that Hammond invites his grandchildren along for the weekend (including, at one point, Hammond himself), Grant quickly embraces the kids' presence. He is immediately drawn to Tim, the young dinosaur expert, he takes on the role of protecting both Tim and his sister, Lex, when the dinosaurs attack. It is unclear why Grant takes on this role. His wife died years ago, so perhaps he regrets the fact that he does not have any children of his own. Most of his research involves the study of baby dinosaurs, the closest thing to children he has ever had. Alternatively, the affinity Grant feels for the children, especially Tim, may be simply due to the fact that they are, like himself, huge dinosaur enthusiasts.
The owner of InGen and a well-known dinosaur fanatic, Hammond invests many years and millions of dollars into the project of cloning dinosaurs. Although his love of the ancient creatures seems sincere, Hammond is also determined to turn the idea into a huge profit. This greed often seems to hamper his judgment, especially when the park starts malfunctioning and several of the people on the island express a desire to shut it down. Hammond is particularly annoyed at the predictions Malcolm makes about the park's inevitable failure. The fact that Malcolm is allowed to visit the island at all betrays the fact that Gennaro has forced Hammond into bringing a team of outside experts in to evaluate his park. Hammond, on the other hand, would like Grant and Sattler to believe that they are there merely as his friends, for social outing and sneak- peek at his park.
Though Hammond claims to have created the park for the children of the world, he modifies this statement by admitting that only the world's richest kids would ever get to see his dinosaurs. Ultimately, all Hammond wants is to make a lot of money. Even after witnessing all the death and destruction his scheme causes on Isla Nublar, he still intends to create another park with the frozen embryos he has in storage. The fact that his death is brought about, albeit accidentally, by his own grandchildren is an ironic final twist.
The reason Hammond hates Malcolm so fiercely probably has as much to do with the way the mathematician presents himself as it does with his gloomy forecast for Jurassic Park. Malcolm represents a new kind of academic, an outgoing, cocky mathematician. He wears all black, flirts with Sattler, and generally acts as if he is the star of the show. The smart-ass, holier-than-thou attitude with which he constantly condemns the park makes us somewhat understanding of Hammond's annoyance. Although Hammond and Gennaro are the only characters who are visibly annoyed by Malcolm's smug self-righteousness, even Grant seems put off by the mathematician's flippant and relentless espousal of chaos theory. Arnold attempts to put Malcolm in his place, claiming he is just another new age science hack who thinks he knows everything because he happens to be an expert on a theory that has recently become trendy and fashionable.
Despite his personality defects, Malcolm is correct in every prediction he makes about the park. It seems odd, then, that Malcolm dies, sharing the same fate as several villainous characters such as Nedry and Regis. Nonetheless, Malcolm's death does, ironically, further support his own confident chaos-theory predictions. His I-told-you-so forecast for the island ends up proving truer than he has perhaps even told himself.
The idea of a dinosaur attack is scary in any light, but Crichton ups the suspense a notch by narrating much of the dinosaur attack scenes from the perspective of Tim, a young boy. We are compelled reader to imagine what this eleven-year-old feels when assaulted by a full-grown tyrannosaurus. Tim makes for a good perspective: he is exceptionally intelligent, mature for his age, thinks quickly on his feet, and has a particular interest in dinosaurs. In fact, Tim often shows that he is more knowledgeable about dinosaurs than many of the "experts" who work at Jurassic Park. In this way, Crichton uses Tim used to show how irresponsibly Hammond and InGen have used science. Dr. Wu does not even know the names of the dinosaurs he is creating, while an eleven-year-old boy knows seemingly everything there is to know about all the animals in the park.
Already familiar with Grant's research when he meets him, Tim immediately looks up to the paleontologist. Tim's parents are in the middle of a divorce, and Lex constantly points out the disparity between Tim's interests and those of his father. His father is a sports nut who simply does not understand why Tim would be fascinated with a dead, ancient species such as dinosaurs. Grant, then, takes on a surrogate father role for Tim, encouraging his thoughts and ideas about the dinosaurs in the park and being a good friend throughout the crisis that befalls the park.