The Dollmaker’s second expedition, along with Luis Wu and the Animal Speaker, to the Ring World. The goal is to find a transmutation device for converting matter. But trouble has already come to the Ring: it is unstable and, in a few years, will collide with a star. The Ring’s defenders are frantically restoring the correction system destroyed by the Builders of Cities—but that is not enough. To restore the orbit, a trillion Ring inhabitants will have to be killed. Who could possibly do such a thing? Listen to the audiobook “Engineers of the Ring World.”