Tonight’s installment is devoted to the advent of color TV – to, that is, the depiction of minorities on television. Previous installments of this series have been frustratingly superficial, but I’m holding out hope that this one will be more judicious about the choices of its clips, guests and narratives. One thing they did right, certainly: land Bill Cosby, who changed television with both I Spy in the Sixties and The Cosby Show in the Eighties, as an interview subject. Check local listings.