Planet Earth has been a familiar concept for a mere fraction of recorded history. Until about the mid-1600s, most humans thought of Earth as immobile, likely either dim or simply invisible from the Moon or anywhere else in the heavens, and not (like the planets) participating in what Galileo called "the dance of the stars." A Universe of Earths retraces the exhilarating story of how all that changed, and how we came to perceive the Earth as a "wandering star." It's a story that has vastly augmented and enriched our understanding of how Earth and its inhabitants fit into the big picture of the Cosmos.

But almost as soon as humans started to grasp that Earth is a planet, many also began wondering if perhaps the other planets might be earths. This bold conjecture ignited the whole gripping history and literature of space travel, of extraterrestrials, of other worlds. And yet the thesis that the Universe is full of other worlds like Earth has from the start been fueled more by imagination than by scientific evidence.

A Universe of Earths offers a surprising alternative to that "other worlds" account, one that releases humans not only from the pre-Copernican view of Earth as low, lowly, dark, a cosmic sump, but also from the persistent modern aspersion of Earth as cosmically ordinary, "mediocre," "dethroned."