The Curious Incident of the Dog in the Night-Time

The census claim is confirmed. The true first is British and consists of TWO simultaneous hardcover issues published 1 May 2003: Jonathan Cape (the adult issue) and David Fickling Books (the children's/young-adult issue). Both are collected as first editions, neither has precedence over the other, and a completist collection holds both. The Doubleday US edition followed in 2003 (sources cite 17 June, one gives 31 July) and is the first American edition — a first, but not the true first. Written in English; no original-language question arises.