Piersons puppeteers, three-leg two-head aliens find immense structure in unexplored part of the universe. Frightened of meeting the builders, they send a team of two humans, a puppeteer and a kzin, eight-foot red-fur catlike alien. Ringworld is 180 million miles across, sun at center. But the expedition crashes, and crew face disastrously long trek. Paperback , 288 pages Published June 9th 2005 by Gollancz (first published 1970)