This will doubtless be confusing to many familiar with the Malory version and its heirs, which showed Gawin in an unfavorable light and used Perceval not at all. But this new novel stands apart, owing much to the mysticism, the legend, the superstition -- the whole pagan overlay of early Christianity. It gives fresh dimension to the ""reasons why"" that are often clouded in the romantic portraits of the Knights of the Round Table. It is overlong, perhaps, and at times the philosophic divergences break the thread of the narrative. But it does make a contribution as another facet of the story that has fascinated audiences through the centuries.