When you think of memorable movie quotes, "Casablanca," starring Humphrey Bogart, may top the list ...

Besides this famous scene between Bogart and Ingrid Bergman, the film also features "Louie, I think this is the beginning of a beautiful friendship." There's even a famous, oft-repeated line that isn't really in Casablanca. 

Denver author Josh Chetwynd explores the genesis and stories behind some of Hollywood's most iconic lines in a new book, "Totally Scripted: Idioms, Words And Quotes From Hollywood To Broadway That have Changed The English Language."

For example, there's this famous scene from "Forrest Gump":

The line, "Life is like a box of chocolate ... you never know what you're gonna get," was never written in the book that preceded the movie, Chetwynd says. Also, he adds, Winston Groom, the author, had a different actor in mind for the role of Gump instead of Tom Hanks, who won the Academy Award for his portrayal.

Chetwynd spoke with Colorado Matters host Ryan Warner.