PEN Literary Award Winner: “The best, most entertaining examination of the possibility of other life in the universe since [Carl] Sagan’s best work.” —Boulder Daily Camera It’s been decades since Carl Sagan first addressed the general public about the possibility of extraterrestrial life from a scientist’s perspective. We’ve learned a lot in those years, and now planetary scientist David Grinspoon investigates the big questions: How widespread are life and intelligence in the cosmos? Is life on Earth an accident, or in some sense the “purpose” of this universe? And how can we, working from the Earth-centric definition of “life,” even begin to think about the varieties of life-forms on other planets? In accessible, lively prose, and using the topic of extraterrestrial life as a mirror with which to view human beliefs, evolution, history, and aspirations, Grinspoon takes us on a three-part journey—the history of our expanding awareness of other planets and our ideas on alien life dating back to the earliest days of astronomy; the science of cosmic evolution and the evolution of life on Earth, including a critique of the “Rare Earth hypothesis”; and the beliefs that humans hold, addressing the limits of our ability to conceptualize or communicate with intelligent aliens and the scientific and philosophical implications of far-future evolutionary possibilities. Rich in personal and often amusing anecdotes, Lonely Planets explores the shifting boundary between planetary science and natural philosophy, and reveals how the search for extraterrestrial life unites our spiritual and scientific quests for connection with the cosmos. Includes a new foreword about recent Mars discoveries “An outstanding introduction to cosmic evolution.” —San Jose Mercury News “[A] terrific book.” —San Diego Union-Tribune “A personable chat on life, the universe and everything.” —Publishers Weekly