Most historians mark the period from the late 1950s, when the networks gained control over TV’s content, to the end of the 1970s as the network era. Except for British and American anthology dramas on PBS, this was a time when the Big Three broadcast networks—CBS, NBC, and ABC—dictated virtually every trend in programming and collectively accounted for more than 95 percent of all prime-time TV viewing. In 2012, however, this figure was less than 40 percent. Why the drastic drop? Because cable television systems—along with VCRs and DVD players—had cut into the broadcast networks’ audience.