Tree of Smoke by Denis Johnson
This is a book full of caves: tunnels used by the Viet Cong in combat; caverns inhabited by indigenous peoples for rituals; darkened grottos perceived by the occupying forces as unsettling emblems of the unknown. Throughout Tree of Smoke, characters explore these caves (real and symbolic), seeking everything from military intelligence to escape (from themselves, from the war) to redemption. In each instance, these caves provide a chance at rebirth. This is not salvation, however, but merely another beginning to another cycle.
Tree of Smoke is a reminder that salvation is just a myth—the ultimate tree of smoke, in fact—and that there are no right or wrong answers, that “good” and “bad” are not absolute, that this life is but one turn on the eternal spiral of existence. This realization, which eventually dawns on each character, is disconcerting and often crippling. But it also provides a strange sense of solace when examined amid the chaos and carnage of the Vietnam War, as it exposes the futility of such a campaign—for without salvation, there is no chance of victory.