Divergent

US Katherine Tegen Books (an imprint of HarperCollins Children's Books), New York, 2011 is the true first. Sources give the on-sale date as either 26 April 2011 (Wikipedia infobox) or 3 May 2011 (retail listings); either way it precedes or is simultaneous with the UK. HarperCollins Children's Books issued Divergent in the UK in 2011 as a paperback (ISBN 9780007420414, listed on sale 3 May 2011) — that is a UK first, not the true first, and collectors chase the US hardcover. Later US reissues, boxed sets, and film tie-ins are "first thus" traps.