The sport of boxing is dying in a last explosion of dollars. Its beleaguered performers are reaching up for a last payday with bravery, one-liners and self-delusion. Fittingly it is in boxing''s capital, in a faded downtown Vegas casino with a hooker for company, that the author, a boxing writer and sometime boxer''s agent, reflects on his own exit from the scene. As the boxing world starts to recede, the characters he has lived with, and for, rear sharply into focus one last time: the astonishing Jack Kid Berg, and Kid Chocolate the Havana Dandy, and ''Sweet C'' McMillan. This Bloody Mary is the journey of an obsession. It started innocently enough. But as it proceeds, the arc lights begin to shift, until even the shadows in the minds of those who inhabit and surround the ring seem caught in their glare.