Robert Wilson, . . Harcourt, $25 (480pp) ISBN 978-0-15-100846-9

This tense thriller from the author of A Small Death in Lisbon (2000) mixes mathematics with wartime intrigue to fine effect. British intelligence hires Andrea Aspinall, a mathematical wunderkind, to make use of her extraordinary gift in hunting atomic secrets. But Andrea disappears in Lisbon, where she adopts a new identity and meets Karl Voss, an attaché at the German legation, who's plotting against the Nazis. The action shifts to Portugal and cold-war Berlin, where intrigue and counter-intrigue are routine, until a bleak ending brings the reader up short. The narrative spans the years from WWII to glasnost and the collapse of the Berlin Wall, yet for all the inevitable social commentary the novel remains at heart a conventional sociopolitical thriller with strong echoes of le Carré, Ambler, Deighton and others—not to mention Gravity's Rainbow. As the story lengthens and the calendar pages fall away, suspense inevitably slackens, though for the most part the novel remains supremely readable. Wilson's spare prose style never becomes skeletal, and the characters, while lightly sketched, remain believable. The author portrays Andrea in particular with sympathy and insight, and adumbrates her remarkable ability early on when she describes what might be called the joys of mathematics: "The number six... has three divisors—one, two and three—which if added together come to... six. Isn't that perfect?" The verdict: an evocative and compelling thriller. 5-city author tour; 75,000 first printing.(Oct. 19)

Forecast:After the success of A Small Death in Lisbon, winner of Britain's CWA Gold Dagger Award, a lot is riding on this follow-up; expect sales to exceed those of the previous novel.