In Ringworld and Ringworld Engineers Larry Niven created Known Space, a universe in the distant future with a distinctive and complicated history. The center of this universe is Ringworld, an expansive hoop-shaped relic 1 million miles across and 600 million miles in circumference that is home to some 30 trillion diverse inhabitants. As in his past novels, Niven"s characters in The Ringworld Throne spend their time unraveling the complex problems posed by their society.