Michael Crichton sold the movie rights for $1 million before the novel was published.
Michael Crichton wrote the character Mark Lewyn for the film specifically with Dennis Miller in mind and the character in the book was somewhat modified for the screenplay to fit Miller's personality.
Milos Forman was originally attached to direct but left the film due to creative differences with Michael Crichton.
After Milos Forman left the project, Barry Levinson and Alan J. Pakula were in contention to take the helm.
Geena Davis was Michael Crichton's first choice for the female lead.
Annette Bening was originally set for the female lead until she fell pregnant. Madeleine Stowe was then considered before Barry Levinson settled on Demi Moore.
As filming neared completion, Caroline Goodall slipped on a water spillage in her home and broke her shoulder. She was able to film her remaining scenes by taking some painkillers and removing her sling.
Caroline Goodall's role as Michael Douglas' wife was beefed up when the actress came on board. In the original novel, the character disappears for most of the latter part of the story.
In Liverpool, England, the film's poster was removed from bus shelters because it was considered too sexually suggestive, especially in light of the fact that Liverpool County Council had just run an ad campaign promoting the safety of their buses to women traveling alone at night.