BLACK SUN by GEOFFREY WOLFF 367 pages. Random House. $12.95.
Harry Crosby, a wealthy Bostonian of good family and, from his relatives' point of view, regrettable literary pretensions, painted his toenails red one December afternoon in 1929 in a Manhattan apartment he had borrowed from an artist friend. He lounged in bed a while, swigging Scotch companionably with his mistress, Josephine Rotch Bigelow, a beautiful young married woman from another prominent Back Bay clan. Then, apparently with her enthusiastic approval, and in the best of moods, he killed her with a pistol, and a...