Larry Niven

World of Ptavvs is a science fiction novel by Larry Niven, first published in 1966 and set in his Known Space universe. It was Niven's first published novel and is based on a 1965 short story of the same name.

Ringworld's Children is a 2004 science fiction novel by Larry Niven, the fourth in the Ringworld series set in the Known Space universe. It describes the continuing adventures of Louis Wu and companions on Ringworld.