Want to be a political journalist or biographical historian? Forget graduate or journalism school. Read Robert Caro’s "Working: Researching, Interviewing, Writing." Caro, a Pulitzer Prize-winning author and recipient of so many other prestigious awards, got them for superb investigative reporting on brilliant, ruthless men. The books include "The Power Broker" about Robert Moses – “the greatest builder in the history of America, perhaps in the history of the world” – and "The Passage of Power," book four of Caro’s five-volume series, "The Years of Lyndon Johnson." Book five, the final book on the man who made the Senate work for the first time in 100 years, notably enacting civil rights legislation before getting bogged down in Vietnam, should be out, he hopes and jokes, “in his lifetime.” He’s 84. What takes him so long? It’s his most un-favorite question, but he addresses it in “Working” – with honesty and humor and in a wonderfully conversational style. It’s as though he’s in your