Read the credits! It's NOT based on Kantor's novel.

Too many people assume that this film is based on the Pulitzer Prize-winning novel of the same name by MacKinlay Kantor. The film and book share many of the same characters who were historical people that really existed, but that's as far as it goes. None of Kantor's fictional characters are in the movie and, more importantly, his name does not appear in the film's credits as having written the novel the film is based on. To increase the confusion, there is a long out of print screenplay-to-book novel out there (again with the same title), but it can't hold a candle to Kantor's massive classic which is not for the feeble-minded.