Since the early 1960's, when the possibility of human space travel became reality, kids and adventurers of all ages have dreamed of going into space themselves. But there is no environment more alien to the human body than the emptiness of space, where temperatures can fluctuate five hundred degrees. In this void, without the protection of a spaceship or a spacesuit, our blood would actually boil. It takes the most sophisticated machines ever built to get into space, and the effects of long-term space travel on the human body are still being studied. So why do so many people want to go? One of most important reasons for exploring space is to see if we're alone in the universe - whether there are other life-forms out there. It's hard to think of a more important question from the point of view of philosophy, religion, or sheer curiosity. In the meantime, the space age is in its infancy, and each generation will push it to the limit. There are no final frontiers.