Joseph Campbell meets the North Vietnamese Army in this ambitious but flawed Vietnam war memoir, in which the author interprets his behind-the-lines operations as a ``mythic hero- journey.'' Stevens (History/Univ. of Hawaii) spent three years in Vietnam, first as a Marine corporal and then as a civilian State Department adviser. While there, he took extensive notes, which along with some archival research form the basis for this fast- flowing book that recreates a series of reconnaissance operations in early 1970 in which Stevens took part. His evocations of these tense, physically punishing journeys inside enemy territory are unique among the hundreds of veteran-penned Vietnam war memoirs. That's because Stevens is not content merely to chronicle his adventures in descriptive prose. Instead, he employs a mixture of dialogue-heavy and metaphor-dense writing in an attempt to elevate his wartime missions into a meditation on the Greater Meaning of It All. ``We're deep in the jungle and outside the law,'' Stevens observes in a typically ruminating passage. ``Our journey is within, too, and back into time. Where will it lead? What will we find?'' This particular journey and those that follow lead to tension-filled days and nights on and near the Ho Chi Minh Trail. They also lead, unfortunately, to a hefty amount of breathless, repetitive, pretentious writing in which Stevens muddies up his narrative with fuzzy literary references. On one page alone the author compares himself and his compatriot to ``Tom and Huck'' and a helicopter ride to ``The Escape of Prometheus,'' makes reference to two Hindu gods, and quotes Walt Whitman. In the words of Carl Jung (as conveyed by the author), this book proves that man ``never perceives anything fully or comprehends anything completely.'' (10 photos, 1 drawing, 3 maps, not seen)