The Engines of God - Jack Mcdevitt

In the far reaches of the solar system, the human race made its most staggering discovery--a colossal statue of an alien creature. The mystery of its origin was never solved. But now, after two hundred years of speculation, the dying planet Earth must prepare for the truth. The first Priscilla Hutchins novel from Jack McDevitt, hailed by Stephen King as the logical heir to Isaac Asimov and Arthur C. Clarke. Humans call them the Monument-Makers. An unknown race, they left stunning alien statues on distant planets in the galaxy. Each relic is different. Each inscription defies translation. Yet all are heartbreakingly beautiful. And for planet Earth, on the brink of disaster, they may hold the only key to survival for the entire human race.