In a career spanning more than forty years, the biographer Robert Caro has written about only two subjects.  But they’re very big subjects: Robert Moses, the city planner who brought much of New York under his control without holding elected office, in “The Power Broker”; and President Johnson, in “The Years of Lyndon Johnson,” of which Caro has completed four of a projected five volumes.  More than life histories, these books are studies of power, and of how two masters of politics bent democracy to their wills.

Caro, who started out as a newspaper reporter, is a completist.  When he was writing about Johnson’s oath of office after the assassination of President Kennedy, Caro referred to a famous news photograph that showed twenty-six people in the room—and interviewed every person still living..  And when Caro realized he had forgotten the photographer, he interviewed him, too. This truly prodigious research is complemented by the elegance of Caro’s prose, which commands rhythm, mood, and sense of place in a way that resembles the work of a novelist.  When he appeared at the New Yorker Festival, in 2017, Caro was interviewed by one of the great novelists working today, Ireland’s Colm Tóibín.