The Korean-American artist Nam June Paik coined the term “information superhighway” in 1974 and even seemed to foresee the internet: “If you create electronic highways,” he said, “something has to happen.” And something did. But Paik was already making things happen, not with digital innovation but with midcentury technology—old radios, TV screens, neon tubing, video imagery. Giant toys for abstract thinkers, Paik’s art still intrigues. With more than 200 works, this is a major retrospective. —L.J.