When the credits rolled after a screening of “Hidden Figures,” my fellow movie-goers applauded enthusiastically. I joined in the clapping for the black women scientists we’d seen portrayed on the big screen and for a movie that made us feel good.

I’m glad I also read Margot Lee Shetterly’s book on which the movie is based. Shetterly made me think.

A movie that exactly replicated a book would be unwatchably long, talky and confusing. Screenwriters need to make choices. They roll several characters into one who can represent the stories without cluttering the narrative. They add a bit of drama to transform events into emotionally resonant metaphor. They crank up the romance to keep us cheering.