Two books in one: first, an inflated, new-agey perspective on space exploration; second, an anthology of comments by 24 astronauts and cosmonauts about their off-Earth experiences. As a partisan of space flight, White has few peers. Exploration of the solar system and beyond, he trumpets, ""will result in a fundamental transformation of the human species, an evolutionary step unprecedented in human history."" How so? White's answer mires him in space-age jargon: Spaceflight is so salutary because it produces the ""Overview Effect,"" in which the Earth is seen as a unified whole in context with the solar system and the universe. And what will this new understanding lead to? Nothing less than three new civilizations, which White dubs Terra, Solarius, and Galaxia--the last two populated by homo spaciens (!), the successor to poor earth-bound homo sapiens. Clearly there's a powerful idea here (that spaceflight is transformative), but White acts like a running back who carries the ball through the goal posts--and right out of the stadium. At least his approach is attractively eclectic, as he draws on evolutionary theory, space technology, and numerous other disciplines to buttress his optimistic, wildly speculative scheme. Ironically, the remarks by spaceflight veterans provide a down-to-earth counterweight to White's flight of fancy. Some of the astronauts echo White's enthusiams, while others toe a skeptical line. But there's uniform enchantment in hearing these firsthand accounts of a wondrous experience that just about none of us will ever enjoy, if White had contented himself with a succinct preface to these words from space, his appealing vision might gather more converts.