An action-suspense novel set in Peru? Why not? Almost all the world's prime exotic locals have been pre-empted by now -- even Antarctica -- and a writer likes to feel that his background is not too shopworn. An expense-account dollar probably goes farther in Peru these days than in Japan or Switzerland. And when you look at it closely, as Laurence Leamer obviously has done, Peru has quite a lot to offer a novelist. Its landscape includes jungles, mountains, the beginning of the Amazon River and beaches internationally famous for surfing. Sociologically, it offers a military government, revolutionary rumblings, abject poverty, a fascinating and ancient Indian culture. And for plot complications, there is cocaine -- endless acres of coca bushes, high up in the mountains, the leaves of which must be worth at least their weight in gold.

Cocaine is the mainspring in "Assignment," a first novel by a journalist who has already won critical acclaim for his nonfiction ("Playing for Keeps in Washington") and could as easily have produced a readable novel about Washington as Peru. What he does instead is take an assortment of Americans down to South America, get them into hot water and generate suspense over how they will get out.

Three young Americans have disappeared in Peru, apparently as part of a struggle for control of the cocaine trade; two of them are relatively unimportant, but the third is Nancy Marne, whose father is the president of the IBS conglomerate -- an international business octopus - whose many holdings include the IBS television network. The story begins to move when Robert Branker, an aging star reporter for IBS's television magazine, "Century," is sent to Peru with a production team to find out what has happened to Nancy. Being a good reporter in a country where people have secrets to hide, Branker quickly gets himself into trouble -- deeper and deeper into trouble as he goes higher and higher into the mountains, deep enough to have soldiers shooting at him after he discovers an enormous, hidden cocaine factory on a remote plateau. He is already in trouble back at the network, with an executive producer who wants to ease him out of the spotlight because he is on the wrong side of 40. And the corporate complications thicken when it begins to appear that IBS may be involved, in some way, in the cocaine war.

So much for plot; Leamer supplies it in abundance -- always interesting and frequently not improbable. He is also a demon for authentic background, whether it is the jungles of Latin America or the steamier jungles of Manhattan. His American characters are practically all media people and have the ring of authenticity, and if some of the more exotic foreign characters owe a nuance or two to Ian Fleming (notably a bad Peruvian cop who is half back and half Chinese), at least he is letting himself be influenced by an authentic master of his genre.

As a first novelist, Leamer's virtues are those of a good reporter -- which he certainly is. The opening pages of the novel are a prime example -- good expository writing, efficient, informative and interesting; but the book reads more like a magazine article than a novel until he gets his characters moving around and talking. Fortunately, he does that quickly, and he has a real ear for dialogue in the American language; he should probably be assigned to write the script for the movie that this novel is obviously intended to inspire.

At times, "Assignment" reads like a travelogue, but it is at least an interesting and fast-moving travelogue. Leamer has obviously been there, although one may doubt that, after his book reaches Peru, he will ever be allowed in again. In little more than 200 pages, he takes the reader to a nightclub and a lower-class bar, a remote village square high in the Andes, Inca ruins, a Peruvian prison (particularly the special compound where American cocaine dealers are held), an enormous, busy and very efficiently organized brothel, and a cocaine factory hidden in the jungle. There is also a hair-raising escape across jungle, rivers and mountains in a small plane that is pursued by a couple of military jets. It should be a highlight of the movie, although it seems slightly tacked-on in the book.

In sum, what we have here in the work of a skilled and seasoned professional, easing his way into a slightly different branch of the profession. To the experienced reader, there are a few hints that this is Leamer's first published novel, but it gives every reason to believe that he will do as well in fiction as he has in reporting.