AMERICA IN VIETNAM: A DOCUMENTARY HISTORY, edited with commentaries by William Appleman Williams, Thomas McCormick, Lloyd Gardner and Walter LaFeber (Doubleday: $19.95, hardcover; $9:95, paperback). The agony and humiliation of America's involvement in Vietnam is presented by four historians through the words of Presidents, secretaries of state and defense, generals and admirals, senators and congressmen, "experts"--and of some of the men who bore the pain and horror of the consequences of their leaders' decisions. "America in Vietnam" offers telling evidence of how the United States became mired in Vietnam, not through evil intent, but through ignorance, expediency and political vanity. The documents reveal the vulnerability and helplessness of individuals in positions of power under the assault of forces they do not fully understand and cannot control. Still, this approach to understanding the Vietnam tragedy should be treated with caution. Within the confines of a single book of little more than 300 pages, the editors are able to present only a small fraction of the enormous amount of documents produced by a major historical event spanning decades. How representative their offerings are must be determined by the reader. And that, no doubt, will be colored by his or her own views of America's longest and most debilitating foreign conflict.