Barack Obama does not say much about his years in New York City. The time he spent as an undergraduate at Columbia College and then working in Manhattan in the early 1980s surfaces only fleetingly in his memoir. In the book, he casts himself as a solitary wanderer in the metropolis, the outsider searching for a way to “make myself of some use.”

He tells of underheated sublets, a night spent in an alley, a dead neighbor on the landing. From their fire escape, he and an unnamed roommate watch “white people from the better neighborhoods” bring their dogs to defecate on the block. He takes a job in an unidentified “consulting house to multinational corporations,” where he is “a spy behind enemy lines,” startled to find himself with a secretary, a suit and money in the bank.

He barely mentions Columbia, training ground for the elite, where he transferred in his junior year, majoring in political science and international relations and writing his thesis on Soviet nuclear disarmament. He dismisses in one sentence his first community organizing job — work he went on to do in Chicago — though a former supervisor remembers him as “a star performer.”

Senator Obama, an Illinois Democrat now seeking the presidency, suggests in his book that his years in New York were a pivotal period: He ran three miles a day, buckled down to work and “stopped getting high,” which he says he had started doing in high school. Yet he declined repeated requests to talk about his New York years, release his Columbia transcript or identify even a single fellow student, co-worker, roommate or friend from those years.