The Citadel of the Autarch

The US Timescape/Simon & Schuster hardcover, New York, is the true first, published January 1983; the UK first is Sidgwick & Jackson, London, March 1983 (ISBN 0-283-98943-2). Both are collected; the US precedes by about two months, and Wikipedia's record likewise gives the country of first publication as the United States with the Timescape ISBN. The census claim of US precedence is confirmed; this volume completes The Book of the New Sun tetralogy.