THE RAVENS The Men Who Flew In America's Secret War in Laos By Christopher Robbins Crown. 420 pp. $19.95 THE KEY TO FAILURE Laos and the Vietnam War By Norman B. Hannah Madison Books. 335 pp. $19.95

IF CAMBODIA was a "sideshow" to America's shattering experience in Vietnam, what was Laos? A secret, forgotten war where American pilots dumped bombs if missions over North Vietnam were aborted. A "cost effective" way to blunt communism for the CIA. A superhighway to the south for the North Vietnamese. A homeland, now lost, for many of its people, including the mountain tribesmen called the Hmong who were armed by America.

Though Cambodia's tragedy has been chronicled in the past few years -- because of the genocide practiced by the victors there, and because the secret bombing of it by the Nixon administration is viewed by some as a case study in the cynicism of American foreign policy makers -- relatively little has been written about the secret war in Laos. British writer Christopher Robbins now offers one view of that war, as seen through the eyes of a band of Air Force officers called "the Ravens."

It is a story that hasn't been told before because much about the secret war in Laos is still classified. The Ravens, never more than a few dozen at a time, were stationed in Laos from the mid-1960s through the American withdrawal from Indochina in 1973. They dressed in civilian clothes because the United States was pretending to honor the neutrality of Laos under the Geneva Accords of 1962. They were not glamorous fighter jocks, but forward air controllers with the radio call sign "Raven." Their job was dirty and dangerous. They flew 12-hour combat days over Laos in light prop planes, directing an increasing volume of U.S. air strikes against both the Ho Chi Minh trail and advances of communist troops in the northern part of the country.

There is a temptation to dismiss this work as almost a comic-book version of war. The pilots were even recruited into something code-named the "Steve Canyon program." Some of the Ravens come across in the book more as airborne Rambos than U.S. military officers. (One can already imagine the movie, with Stallone swaggering and wearing a "Nevermore" shoulder-patch).

Robbins has written an adventure story. And at times he admires his heroes so much that the book becomes too much a blur of individual "war stories." He describes the CIA's pet black bear, Floyd, who could drink with the best of the bunch stationed at the secret headquarters of Hmong general Vang Pao; the exploits of the revered Hmong pilot Lee Lue who lived up to his motto, "Fly till you die"; the bend-the-rules antics of Ravens who flew down to Udorn, Thailand -- support base for the secret war -- to steal everything from a cook to a fighter plane.

Robbins also recounts details of the loss of a secret radar station and of about a dozen Air Force personnel, posing as civilian contractors, who died there, after a North Vietnamese attack on a mountain in northern Laos in March of 1968. He notes that the Air Force hid behind the secrecy of the war in Laos for nearly 20 years before telling the wife of one of those killed how he died.

Robbins doesn't pretend that his is a comprehensive examination of the nuances of policymaking that Washington knows so well. But there is more to the book than grist for B-movies. The Ravens does remind us of several lessons about the limits of American military power.

Some of the Ravens began to question the continued bombing, which demonstrated the capacity of U.S. air power, if not its value. The Air Force dropped 1.6 million tons of bombs on Laos during the war years, more than it dropped on Germany in World War II. Eight times more than it dropped in the secret bombing of neighboring Cambodia. More than half a ton for every man, woman and child in the country.

A major reason the Ravens were so busy in Laos in the late 1960s is that the Air Force had so many planes, pilots and bombs committed to southeast Asia it couldn't find enough targets to obliterate. When President Johnson or President Nixon called a temporary bombing halt over North Vietnam, the Pentagon brass simply shifted their attention to Laos.

The recent hand-wringing of members of Congress over how they were deceived about secret White House aid to the contras, for instance, is just the latest repetition of laments about secret wars, like the one in Laos.

Robbins even makes a reference to the fact that Richard V. Secord, ramrod of Ollie North's secret army, helped direct the air war in Laos from Thailand in the late 1960s, while two other more minor Iran-contra players, Theodore Shackley and Thomas Clines, were CIA officers in Laos.

PERHAPS the most poignant reminder of the limits of American power is Robbins' sympathetic portrayal of the pilots' genuinely affectionate relationship with the Hmong, who became refugees after the U.S. withdrawal. Some 68,000 Hmong now live in the United States, struggling to adapt to a new culture. Robbins says he has agreed to give part of his earnings on the book to a Raven program to aid these people -- living reminders of one of America's secret wars.

In The Key to Failure: Laos and the Vietnam War, Norman B. Hannah, a retired State Department official who served in Southeast Asia during the war, takes a strategic view. His thesis is that the United States focused its efforts in Indochina on the wrong target, South Vietnam, when it should have been fighting on the ground in Laos. Hannah quotes from a series of memos he wrote at the time encouraging such a course, making his book at times a one-man chorus of "I told you sos."

There is no mention of the Ravens in this book. Their effort with the Hmong in the northern part of Laos rates a short, if admiring, footnote about the "superbly conducted and largely covert campaign" in support of the Lao government and "doughty" mountain tribesmen. There was a "tacit agreement," he writes, that North Vietnam wouldn't take over the northern part of Laos if we wouldn't deprive Hanoi of its use of the Ho Chi Minh trail.

Thus the "contest" in northern Laos had little effect on the main event in the south, Hannah writes. That must be comforting news to the Ravens, and the Hmong.

Charles Babcock, a reporter on the Post's investigative staff, has written about U.S. special operations military forces.