The GCHQ team's second puzzle book - full of both harder and easier brain teasers - is the perfect gift for anyone who loves a challenge.

'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

'Fiendishly tricky' Daily Mail

With their first bestselling book, The GCHQ Puzzle Book, the UK's intelligence and security experts tested us with puzzles, codes and real-life entrance tests from their archives.

Now, they are back with a NEW collection of head-scratching, mind-boggling and brain-bending puzzles that will leave you pondering for hours.

For those who often found themselves stumped with the first book, there will be even more starter puzzles to get those brains warmed up. Puzzle aficionados needn't worry though, as there will also be an 'Even Harder' section to test everyone to their limits.

Not only that, but in celebration of GCHQ's centenary, the puzzles in this new book will sit alongside stories, facts and photos from the organisation's first 100 years at the heart of the nation's security. From the Government Code & Cipher School, to Bletchley Park, through to protecting against cyberattacks, the security of our country is in the hands of GCHQ. With this book, you'll get exclusive snapshots into the organisation that keeps us all safe.

If you haven't yet tested yourself with the first instalment of The GCHQ Puzzle Book, check it out now!