After a 14-year-hiatus, SFWA Grand Master Frederik Pohl returns to his multiple- award-winning Heechee series. Using the technology left behind by the alien Heechee, humans have settled all over the galaxy. The Heechee themselves have moved to the galactic core in an attempt to avoid the Kugel, a race bent on genocide. Many humans have joined the Heechee at the core, and some have used the Heechee method of electronically copying their personalities, making them in effect immortal. But this idyllic--and complex--lifestyle is threatened both by the Kugel and a madman, Wan Enrique Santos-Smith, whose xenophobia could result in the destruction of all life.