PAPER LION by George Plimpton. 362 pages. Harper & Row. $5.95.
Many men dream of being George Plimpton: handsome, rich, aristocratic, reasonably young (39), friend of Jackie Kennedy and Marianne Moore, sportsman, writer, world traveler, editor of Paris Review. Plimpton, on the other hand, dreams of being many men. He sees himself as a superathlete—or as several superathletes. His vision is not as remote as other Mittyesque mirages, for Plimpton has found a way of acting out his fantasies.
In 1959, he fought three rounds with Archie Moore, who gave him a bloody nose....