“The line between art and life,” Allan Kaprow said, “should be kept as fluid, and perhaps indistinct, as possible.” It was this philosophy that saw Kaprow, in the 1950s, pulling away from traditional forms of expression. He had trained as as painter with Hans Hofmann, but he also studied composition with John Cage and that’s what took. Kaprow, who died in 2006, became known as the Father of Environments and Happenings, those spontaneous interactions that combine performance art with the visual arts, and create an aesthetic experience never to be repeated. This retrospective traces Kaprow’s development, starting with his later years and heading backward to his beginnings. —E.C.