What would you do if your sister disappeared without a trace? Sister is the Sunday Times and New York Times bestselling debut novel by Rosamund Lupton. It has been translated into over thirty languages and was the fastest-selling debut of 2010 by a British author, a BBC Radio 4 Book at Bedtime and was winner of the Richard and Judy Best Debut Novel of 2011 Award and the Strand Magazine Critics First Novel Award.