The Citadel of the Autarch (The Book of the New Sun, #4)

The Citadel of the Autarch is a science fantasy novel by American writer Gene Wolfe, first released in 1983. It is the fourth and final volume in the four-volume series The Book of the New Sun. In 1987, Wolfe followed this fourth volume with a coda novel entitled The Urth of the New Sun, after complaints from readers that it ended abruptly and without an adequate sense of conclusion. Many consider The Urth of the New Sun to be the fifth and final part of the series.