In this fascinating and cutting-edge work, Dr. Ben Bova explores one of the most thrilling and elemental questions humanity has ever posed: Are we alone? From Copernicus to the advent of SETI and beyond, Bova takes his readers on a tour of the scientific and political battles fought in the pursuit of knowledge and speculates on what the future may hold.

Can life exist outside the planet Earth? The first question one should ask is: How is it possible for life to exist within Earth's brutal confines? On our own world, creatures exist -- and thrive -- in environments first thought to be completely alien and inhospitable. From the rare air of the upper atmosphere to the depths of the oceans, life persists amid crushing pressures, crippling heat, and absolute darkness. Bacteria brought to the moon have survived for years without water, at temperatures near absolute zero, and in spite of radiation levels that would kill human observers. With such resilient and tenacious creatures, it seems that life could spring up, and survive, anywhere.

Many skeptics believe that finding life outside our solar system will never occur within our lifetime -- but perhaps it's unnecessary to look that far. Our neighboring planets may already serve as havens for extraterrestrial life. Scientists have already identified ice caps on Mars and what appears to be an enormous ocean underneath the ice of Jupiter's moons. The atmosphere on Venus appeared harsh and insupportable of life, composed of a toxic atmosphere and oceans of acid -- until scientists concluded that Earth's atmosphere was eerily similar billions of years ago. An extraterrestrial colony, in some form, may already exist, just awaiting discovery.

With the development of new technology, such as the space-based telescopes of NASA's Terrestrial Planet Finder (TPF), we may not have to leave the comfort of our home world to discover proof of life elsewhere. But the greatest impediment to such an important scientific discovery may not be technological, but political. No scientific endeavor can be launched without a budget, and matters of money are within the arena of politicians. Dr. Bova explores some of the key players and the arguments waged in a debate of both scientific and cultural priorities, showing the emotions, the controversy, and the egos involved in arguably the most important scientific pursuit ever begun.