THIS book is about a visible man, a man of action and news.  J. What American today is so starkly floodlit, so thronged by reporters and sociologists, so chronicled and photographed, debated and diagnosed, as a young black male, single, fatherless, violent, now in the hands of the police .... So begins George Gilder’s new book, and continues: “...[T]he invisible one today, surely, is not the jobless youth of the streets, or even the welfare mother, but the successful middle-class black with the stable family and ascendant career... As he succeeds, he is explained away; he is young Tom Token say journalists, educators, government officials, and even leaders of his own ‘community,’ and really, if the truth be known, white at heart.”