This dissertation investigates the Big Three American commercial television networks’ responses to the industry upheavals of the 1970s and early 1980s, specifically those that altered program scheduling practices. During those years, the Big Three faced the FCC’s shifting approach to regulation, the introduction of VCRs, the growth of cable television, and the accompanying increased competition as specialty cable channels and Superstations burst onto the scene. Those changes not only challenged the networks as the primary sources of television programming, they threatened to undermine the temporal structure of television that the networks had developed to coordinate viewers and to feed them through their programming and to their advertisers. This dissertation examines how the Big Three responded to the establishment of the Prime Time Access Rule, the proliferation of cable channels, CNN in particular, and the introduction of the VCR to the American market. Furthermore, it analyzes the fallout from these events and how they influenced the timing of prime time, the length and flow of the broadcast day, and evening news viewing rituals. Although the television schedule is central to the American commercial television networks’ business model, it became clear that the Big Three overlooked television’s temporality in their responses to the changing television landscape.