I spy with my little eye; NATIVE SPEAKER by Chang-rae Lee, Granta pounds 9.99

THIS is the kind of first novel which impresses liberal critics at magazines like the New Yorker or Vanity Fair: a vivid American immigrant's world - in this case, the world of Korean New York - converted, via a year or two on a postgraduate creative writing programme, into the cool, knowing prose of WASP fiction. Chang-rae Lee went to the University of Oregon; while he was there he evidently read plenty of Paul Auster, to judge by the way this cross-cultural detective story splits and coils without getting into knots.

Henry Park is a spy for a private surveillance agency, which provides information on local politicians for unnamed clients while remaining nicely disguised as "consultants of ambient lighting to military installations". He is assigned to tail a Korean-American city councillor called John Kwang who is preparing to run for mayor. All he has to do is infiltrate Kwang's nascent campaign, keep his eyes open, and send reports back to base by modem. But Park has been losing his nerve, ever since he got too close to his previous subject; now, his shared nationality and sympathy with Kwang start to make his betrayer's life unbearable.

It's the premise of any number of thrillers. But Lee's educated language elevates it: the late afternoon sun "warmly lamps" a room; Park tries to justify his spy's calling by "the need in me still to undo the cipherlike faces". And Park's dilemmas unlock a cavernous store of memories and musings on his Korean culture which he has previously bolted shut. His father owned a scattering of grocery shops, sweeping up rotten fruit and battling shoplifters for long hours ("the great mystery to an immigrant's success"), but never letting himself or his son become true Americans. Then Park slowly escaped, diluting his Korean identity by marrying a pale New Englander and learning the tough-guy New York talk of his fellow spies.

Lee flavours all this with zesty smells and sweaty scenes in Korean barbecue shops. But he enjoys Park's (and his own?) memories too much; the plot slows repeatedly as some small detail - the texture of Kwang's hair for example - sets off a long chain of family reminiscence. Lee is also too fond of opaque would-be profundities, especially about Park's marriage: "Her answer was also, of course, a means of renunciation, itself a denial of everything I wasn't offering."

When he puts his existential thriller writer's hat back on, Lee is much more zippy. Park burrows into Kwang's organisation despite his doubts, and watches a campaign gelling though streetcorner rallies and the painstaking registration and tapping of the Korean community. The minutiae of city campaigning are opened up with images and insights where no new ones seemed possible. And every character seems to be writing something - Kwang's staff with their indexes of donors, Park with his reports on Kwang, Park's superiors with their reports on Park - enabling Lee to expand on Auster's idea of detective-as-novelist and novelist-as-detective, while adding in the question of immigrant identity as well.

Park's secretive nature - characteristically Korean, Lee implies - comes under strain as he tries to serve himself, his wife, his masters and Kwang, who places more and more responsibility on him as he notices his writer's talents. For the first time Park has to tell his wife he's a spy, and he grows into an attractively agonised figure, convinced the (white) mayor of New York is funding his spying to stall Kwang's challenge. The story gropes for an end slightly, fumbling a bomb explosion and a Chappaquiddick- style car accident; but by then Lee has written enough cleverly suggestive pages to justify those university fees.