“When you’re making video,” Bill Viola said in 2009, “you’re giving structure to time, which is what a composer does.” In Slowly Turning Narrative, a video installation that hasn’t been shown for almost 20 years, Viola composes. Two screens depict life. The first flies through pivotal moments—birth, death, and the milestones in between—and the second shows a close-up of Viola’s head, chanting “the one who lives,” “the one who acts,” “the one who reads.” In his customary way, Viola is time’s puppetmaster. —E.C.