Relentless is Simon Kernick's fifth thriller and crime novel originally published in June 2006. Its sales were helped by the book being one of Richard & Judy's Summer Book Club recommendations in 2007. It was the 8th best-selling paperback, and the best-selling thriller in the UK in the same year. It has sold over 300,000 copies and was the 4th most borrowed book from UK libraries in 2008. The Guardian summed up its review of the book with "pretty much unputdownable".A review in The Times called it "a fine performance" with "down-to-earth realism" but marred by a parallel with an English football match during a date and time when there would be no games in real life. A review in The Independent wrote "this is probably Kernick's best novel yet". Reviews from readers are considerably less uniform. Criticisms include implausible plot elements, poor research, shallow characterisation and gratuitous violence/swearing. Source: Wikipedia (en)