Riveting and timely, a look at the research that is transforming our understanding of the cosmos in the quest to discover whether we are alone. For thousands of years, humans have wondered whether we're alone in the cosmos. Now, for the first time, we have the technology to investigate. The question should have an obvious yes or no. But once you try to find life elsewhere, you realize it is not so simple. How do you find it over cosmic distances? What actually is life? As founding director of Cornell University's Carl Sagan Institute, astrophysicist Lisa Kaltenegger built a team of tenacious scientists from many disciplines to create a uniquely specialized toolkit to find life on faraway worlds. In Alien Earths , she demonstrates how we can use our homeworld as a Rosetta Stone, creatively analyzing Earth's history and its astonishing biosphere to inform this search. With infectious enthusiasm, she takes us on an eye-opening journey to the most unusual exoplanets that have shaken our worldview - planets covered in oceans of lava, lonely wanderers lost in space, and others with more than one sun in their sky! We also see the imagined worlds of science fiction and how close they come to reality.