 Universal paid Crichton a further $ 500 @,@ 000 to adapt his own novel , which he had finished by the time Spielberg was filming Hook . Crichton noted that because the book was " fairly long " his script only had about 10 to 20 percent of the novel 's content ; scenes were dropped for budgetary and practical reasons , and despite the gory descriptions , the violence was toned down . Malia Scotch Marmo began a script rewrite in October 1991 over a five @-@ month period , merging Ian Malcolm with Alan Grant . 
