A first for Hall's indefatigable field agent (Quiller Meridian, 1993, etc.): After six weeks of numbing inactivity in the corridors of London, he agrees to let a rogue supervisor run him in a clandestine operation. The operation that Flockhart, the control, has set up is so hush-hush that he can tell neither the Ministry nor Quiller just what it is, only that Quiller's initial goal is to gather information on Pol Pot, whose Khmer Rouge is once again casting an ominous shadow over Kampuchea. Though he doesn't trust Flockhart- -when was the last time Quiller really trusted anybody?--Quiller agrees to run the operation on a need-to-know basis under a total blackout. The mission may be exasperatingly secret, but it's not boring. When his Cambodian contact, Parisian photojournalist Gabrielle Bouchard, points out the minister of defense at a neighboring table in their restaurant, Quiller follows him and kills his would-be assassin from the Khmer Rouge; from then on, it's bam, grunt, moan, as Quiller trades body blows with Khmer Rouge types in standard-issue skirmishes from Phnom Penh to Pouthisat to the darkest jungle. Meantime, he's got the information Flockhart wanted so badly--Pol is seriously ill, and his second-in- command, General Kheng San, is ready to launch a bloody offensive- -and doped out the not-very-subtle reason he was sent into the field: Flockhart was laying the groundwork for a bid to authorize air strikes against Kheng. But when the authorization isn't forthcoming, Quiller refuses to take Kheng out in cold blood (clearly the scenario Flockhart had in mind all along), until a final, foreseeable twist clears the air once and for all. Heavier on superannuated public-school types than on memorable adversaries or adventures, with measured outbursts of violence as mannered as Restoration comedy. Surely Quiller's been out in the field long enough to consider an honorable retirement.