Of contemporary sorcerers, one stands alone. Lasse Viren, now 27, in perfection of that other fine Finnish tradition of running long distances, won the 5,000 and 10,000 meters in the 1972 Olympic Games in Munich. In 1976, in Montreal, he won both races again, a defense never before accomplished. In Moscow in 1980 Lasse Viren will run yet again and may well win twice more. But the circumstances of Viren's career and character—his many poor races in non-Olympic competition, his carefully kept privacy, his mildly sarcastic way with curious reporters—have evoked a storm of accusations. It is said that his medals were won with the help of "blood doping," a misleading term for an experimental technique whereby some of an athlete's blood is withdrawn and the oxygen-carrying hemoglobin extracted and stored. When the athlete's system has regenerated the missing red blood cells in a few weeks, the hemoglobin is returned, giving the recipient a higher concentration than can occur naturally. Since distance running depends on oxygen-carrying capacity, the runner, theoretically, prospers.