S6E13. Experiencing a vision from the Prophets, Sisko sees himself as Benny Russell, a science-fiction writer in the 1950s, who struggles with civil rights and inequality when he writes the story of Captain Benjamin Sisko, a black commander of a futuristic space station. 

A singular episode of Trek, a powerful hour of TV, and completely emphatic, empathetic, and accessible science fiction. If you were only going to give Star Trek one and only one look, make it this one.