Thomas' first just-suppose is conceivable enough: two years from now, the Soviets will have built the speediest warplane ever, equipped with flawless antiradar and with thoughi-control for instantaneous weapon firing (electrodes in the helmet). His second takes a bit more of a gulp: rather than steal the plans or the scientists behind the most serious threat ""since the development of nuclear weapons by the Soviet Union and China,"" England (with US assist) will steal the plane--by sneaking in a super-pilot on the day of the test flight at Bilyarsk, 600 miles east of Moscow. Twaddle? Indubitably, but twaddle worth swallowing when each moment is precisely, tautly linked to the next, one tension releasing while another starts to build--like a domino fall in slow motion. American Mitchell Gant, an ""emotional cripple"" haunted by nightmares and psychic brownouts since Vietnam, is the Russian-speaking flier who's passed from one treasonous Russian to another (Jews and dissidents ready to die) until he reaches the concentration-camp-like air base. While the Soviet bureaucrats panic, aware that something--but what?--is afoot, Gant kills and replaces the real test pilot and flies off towards a sky-high duel (remember that thought-control) and a refueling rendezvous on an ice-floe runway in the Barents Sea. With interwoven pockets of action on the road, in the air, in London and Moscow, this is a varied and skillful exercise in non-cerebral but decidedly non-neanderthal suspense.