The GCHQ puzzle book 11

You don't need to be a quiz champion or Mensa member - unravelling these puzzles requires lateral thinking and ingenuity; both can be easily developed.

Step into the mind of a codebreaker as you learn to spot patterns, break ciphers and tackle authentic entrance tests. Sometimes you'll have to work out the question before you start to figure out the answer!

In celebration of GCHQ's 100th year, the intelligence, security and cyber agency has brought together these mind-bending puzzles that are peppered with stories from the organization's incredible history; stretching further back than Bletchley Park, learn how GCHQ has kept the country safe in secret since 1919.