In 1959, the Soviet probe Luna 3 took the first photographs of the far side of the Moon. Even at low resolution, the images stunned scientists: the far side looked like a vast expanse of mountain ranges, rather than the vast lava plains covering the side visible from Earth. Subsequent missions confirmed this discovery with high-quality images. Why does the Moon look this way and can it say something about our place in the Universe? It turns out it can—and quite a lot. In When the Earth Had Two Moons, renowned planetary scientist Eric Asphog takes us on a fascinating journey to the furthest reaches of our Galaxy to discover why the Moon is so different. Engagingly written, with provocative arguments, this book is not only a mind-bending astronomical tour, but also an in-depth exploration of the origins of life billions of kilometers from our home.