As an American schoolboy in Mexico, Kandell relates, he wondered why ""there was never a sustained frontier drive in South America."" Why did the conquistadores and missionaries fail, and the early-20th-century rubber boom collapse? Why no Manifest Destiny in the South? Later, covering the continent for the New York Times (for five years, in the 1970s), he interviewed Peru's past-and-future president Fernande BelaÃºnde Terry--visionary proponent of a highway through the interior, from northwest to southeast. Here, he roughly follows BelaÃºnde's route--assessing the current penetration in light of the past, comparing his recollections from the '70s with conditions today, bringing to greater Amazonia far more than previous writers' preoccupation with Indians, ecology, and frontier exotica (cf., most recently, Amazon, by Brian Kelly and Mark London, 1983, p. 1081). The long failure to settle the frontier he ascribes to white South American fear of ""the savage natives and natural forces of the backlands""; instead they turned outward, to Europe and the US, for culture and trade. And his conclusion, dramatically withheld for the journey's length (a device, but an effective one), is that the wilderness has been breached at last, prospectively giving South Americans nothing less than an identity. The new push will persist because it is taking diverse forms--private and governmental, planned and spontaneous--and proceeding despite setbacks and barriers. In the Peruvian hinterlands, we visit Occidental's isolated, punishing oil fields--and accompany an ailing, troubled worker to a folk healer. (Kandell, taking part, has a hallucinogen scare.) The rubber drive failed, we learn in western Brazil, when nothing was done to meet Asian competition--founded on British domestication of Amazonian wild rubber. The remaining, seduced-and-abandoned rubber-tappers (one of many fine first-person stories) have recently fought to hold their property against incoming cattle ranchers. Meanwhile, agricultural development of most of the Amazon basin--a pet project of the military government, but also undertaken ""without careful research and preparation""--has proved a fiasco: stripped of its lush, self-sustaining vegetation, the land is infertile. The exception is Rondonia, on the southern fringe, suitable for perennial crops (coffee, cocoa, fruit trees) that provide a continuous soil-cover; there, a variegated influx of Western-American proportions is taking place (though not without further Indian losses, and further land-ownership conflicts). In Bolivia's beyond, the coming thing is cattle, the present money-maker cocaine (a sudden clampdown, Kandell suggests, would provoke a revolt); in chronically depressed Paraguay, a vast hydroelectric project is shaping up--which may largely benefit get-ahead Brazilians. With personalities, insights, ironies--and a strong thesis: the book that might open North American eyes too.