 Michael Crichton originally conceived a screenplay about a graduate student who recreates a dinosaur ; he continued to wrestle with his fascination with dinosaurs and cloning until he began writing the novel Jurassic Park . Even before publication , Steven Spielberg learned of the novel in October 1989 while he and Crichton were discussing a screenplay that would become the television series ER . Spielberg considered that what really fascinated him was that Jurassic Park was " a really credible look at how dinosaurs might someday be brought back alongside modern mankind " , going beyond a simple monster movie . 
