Day after day, night after night, the desperate men come and sit in the black chair next to Charles Barber's desk in a basement office at Bellevue and tell of their travails, of prison and AIDS and heroin, of crack and methadone and sexual abuse, and the voices that plague them. In the silence between the stories, amid the peeling paint, musty odor, and flickering fluorescent light, Barber observes that this isn't really where he is supposed to be.   How this child of privilege, the product of Andover and Harvard and Columbia, came to find himself at home among the homeless of New York City is just one story Barber tells in Songs from the Black Chair. Interlaced with his memoir, and illuminating the nightmare of mental illness that gripped him after his friend's suicide, are the stories of his confidants at Bellevue and the "mental health" shelters of Manhattan--men so traumatized by the distortions of their lives and minds that only in the chaotic aftermath of 9/11 do they feel in sync with their world. In the intertwined narrative of these troubled lives and his own, Charles Barber brings to shimmering light some of the most disturbing and enduring truths of human nature.