The Twelve was placed on the Best of 2009 lists by both The New York Times and Los Angeles Times, and the "Ultimate Summer" list by the Daily Mail. The book has been given full reviews in a number of publications in the United States, Ireland and the United Kingdom, appearing in The New York Times, The Irish Times, Los Angeles Times, Publishers Weekly and The Guardian, among others.

Collusion, the sequel to The Twelve, will be published in the United Kingdom by Harvill Secker in August 2010, and in the USA by Soho Press in October 2010.

The Ghosts of Belfast, the American edition of The Twelve, won the Mystery/Thriller category of the Los Angeles Times Book Prize in April 2010. It also won the New Voice category of the 2010 Spinetingler Awards, and was nominated for the 2010 Dilys Award, Anthony Award, Barry Award, and Macavity Award.