This book tells the incredible story of the birth of a whole new field of science called Astrobiology. In the 1990's, powerful new ground - based telescopes plus space telescopes placed in orbits high above earth's atmosphere allowed astronomers to begin discovering that our sun is not the only star in our galaxy to have planets circling it. These new planet hunters (as they called themselves) quickly found that planetary "homes" for extraterrestrial life-forms might be relatively common in the universe. A few years earlier, beginning in the mid 1970's, our life scientists also made a series of startling new discoveries that forced them to question their long held belief that life might be an extremely complicated and fragile process that requires equally complex and fragile environments for it to happen. Single-cell bacterial like organisms were suddenly found living on our planet in extreme hostile environments that everyone believed should instantly kill any normal forms of earth life. Some of these creatures lived in extremely hot or even boiling water which was extremely salty, acidic, or alkaline. A few chose to make their homes inside icebergs, while still others chose even more bizarre environments, such as inside rocks located miles below ground or on the power rods or coils inside nuclear power plants. These life-forms appear to be the direct descendants of the earliest life that managed to evolve almost four billion years ago when our world was extremely hot and believed to be totally unfriendly to any forms of life that we are familiar with today. Our scientists now realized that life, even earth life, may be far more resilient and adaptive to extreme living conditions than previously thought possible and might be able to survive in extreme environments that might exist of other worlds in the universe. And it was not just the planet hunters and the life scientists that experienced a sudden reality check at the end of the 20th century as a result of the rise of computers. Our earth scientists also now discovered that the earth, instead of being a passive ball of rock and gases, was a dynamic changing entity that had been able, over billions of years following its formation, to undergo complex physical changes in conjunction with life itself (i.e., to co-evolve) to produce an incredibly life friendly biosphere that today is literally teeming with fantastic varieties of life virtually everywhere and anywhere we choose to look. Our space, life, and earth scientists now have the technology they need to move from speculating or fantasizing about life on other worlds to possibly providing mankind with the first definitive proof that we are not alone in the universe.