GCHQ (Government Communications Headquarters) is a signals intelligence and cyber security organisation whose mission is to keep Britain safe from terror attacks and cybercrime.
This isn't your grandfather's Sudoku book. Rather, it's a puzzle compendium put together by the organisation that made the Bletchley Park breakthroughs - quizzes, bewilderments and brainteasers to challenge even the sharpest of minds—The Gentleman's Journal The fiendishly difficult puzzle book is back. This is the perfect gift to fuel his ludicrous presumption that he could have definitely been a spy - even better if he's already dog-eared the first version—Huffington Post