Season 6, Episode 13. Unusual synaptic patterns in Sisko's brain send him back to the 1950s, where he experiences racism as a struggling science-fiction writer. Although Star Trek has been noted for its commentary on racism and racial relations since its debut in 1966, according to an article written for the Journal of Popular Film and Television, this episode in particular is considered to have the most "overt discussion of white supremacy and black identity."
