Ringworld's Children is a 2004 science fiction novel by American writer Larry Niven, the fourth in the Ringworld series set in the Known Space universe.

[1] It describes the continuing adventures of Louis Wu and companions on Ringworld.

The novel's plot is largely concerned with the so-called Fringe War.

All the intelligent species of Known Space are interested in the Ringworld.

In the novel, they engage in a Cold War of sorts (actually begun in the previous novel, The Ringworld Throne) on the fringe of the Ringworld star system.