Written in an informal manner, this account tells the incredible story of the creation of an entirely new field of science called astrobiology--a field that is now investigating whether life might exist on other planets. From the discovery that other stars in our galaxy are also circled by planets to the detection of single-cell organisms found living on Earth in extremely hostile environments, this book details the recent breakthroughs made by astronomers and earth scientists over the last few decades. Based on these findings, it argues that scientists now have the technology they need to progress from speculating or fantasizing about extraterrestrials to possibly providing mankind with the first definitive proof that we are not alone.