Probability Moon (The Probability Trilogy Book 1)

Probability Moon is the first book in a space opera trilogy by Hugo and Nebula Award–winning author Nancy Kress. Humanity has expanded into interstellar space using star gates—ancient technological remnants left by a long-vanished race. However, this expansion has come at a cost. Among the stars, humanity encountered the Fallers, an alien race committed to genocide. The resulting war is going badly for humanity. When a new planet is discovered inhabited by a pre-industrial civilization that experiences "shared reality"—a state in which inhabitants are compelled to share the same worldview—a team of human scientists is sent for first contact. Unknown to the team, their mission is actually a covert military operation. One of the planet's moons is revealed to be a massive artifact of the same origin as the star gates, and it may hold the key to humanity's survival in the war.