Question: is first blood based on a true story

Answer: No, Various scripts adapted from Morrell's book had been pitched to studios in the years since its publication but it was only when Stallone decided to become involved with the project that it was finally brought into production. Stallone's star power after the success of the Rocky films enabled him to rewrite the script, to make the character of John Rambo more sympathetic. While Morrell's book has the Rambo character kill many of his pursuers, and Kozoll and Sackheim's draft had him killing sixteen people, in the movie Rambo does not directly cause the death of any police or national guardsmen. Stallone also decided to let Rambo survive the film instead of keeping the book's ending where he dies. A suicide scene was filmed but Kotcheff and Stallone opted to have Rambo turn himself in at Trautman's urging. Stallone did an estimated seven revisions of the script. Kotcheff requested further work be done on the script, which was performed by Larry Gross and David Giler.