As artists gained access to the technologies of television production in the 1960s and 1970s, many began to build their own tools for electronically processing analog video signals to produce novel visual effects. For many artists, the construction and use of mixers, keyers, colorizers, and scan processors became the basis for aesthetic and critical engagements with electronic technologies, as well as collaboration with engineers. This expansive book consists of forty-three chapters by thirty-one authors—most of them artists or curators, many of them also participants in this history—on the people and machines that made up video processing in the United States.