By Robert Caro, Alfred A. Knopf, New York, N.Y., 712 pages, $35.00

In the fourth volume of his biography of President Lyndon B. Johnson, historian Robert Caro tells a compelling story of miscalculation, humiliation, desperation, and redemption. Like all of Caro’s books, this one focuses on “power.” Through assiduous research, Caro paints the portrait of a flawed man who was at once both supremely confident and deeply insecure about himself.