Conundrum , my book of codes, ciphers and challenges, has been given a shiny new cover ready for the Christmas season. The ultimate trial of knowledge and cunning, Conundrum features 200 cryptic puzzles and ciphers. The solutions link throughout the book – so you need to solve them all to get to the final round.

With a focus on ciphers and codebreaking, Conundrum contains twenty sections, each built around a specific subject from music to literature, physics to politics. To take on Conundrum you need good general knowledge and the ability to think laterally. But if you need help, there are plenty of hints to point you in the right direction.

We've all got difficult-to-buy-for people this time of year. This is a chance to give them the chance to join the 18 people worldwide who have so far succeeded in this ultimate challenge.

Note that the version with the new cover is not on sale in the US, but the content of the US version is identical.

You can buy Conundrum from Amazon.co.uk, Amazon.com and Bookshop.org

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