What should a sequel be? It's a simple enough question, yet after more than 100 years of cinema—and 40 years of the blockbuster franchise era—it doesn't feel like we're any closer to a reliable answer ...

The only black people in Ridley Scott’s Blade Runner are extras. The replicants are all white, and the city of Los Angeles is basically an unmixed population of whites and Asians. The Asians live on ...