This is a book about Vietnam, and for straight, readable reportage, it is beyond doubt the best so far: It is also a book about reporting, specifically the difficulties involved in reporting on so confusing and misunderstood a story as Vietnam has been for so long. Lastly , it is a book about the all-important lessons such a story holds for the American public and their policy makers. Mr. Halberstam, posted to Saigon by the New York Times at the age of 27 after brief but distinguished service in the first phases of the Congo crisis, stayed on through the coup which finally ousted the Ngo regime. His accounts of progress--rather, the lack of it--in the war against the Viet Cong, and of the incredible political scene, ran counter to our official line of "cautious optimism" and brought him a great deal of harsh criticism from high places as well as the Pulitzer prize. This more complete version of what he saw contains a splendid sense of the place and the people, as well as an invaluable explanation of the many basic, interlocking problems to be faced there. His chronicle ends before the emergence of General Khanh, but his verdict is in no sense outdated by subsequent developments. South Vietnam "may be worth a larger commitment on our part," he says, "but, if so, we should be told the truth, not spoon-fed cliches as in the past." Perspicacious, pertinent.