Clarity Media Ltd The Junior Code Breaker Book: 50 intriguing code puzzles to crack: can you solve them all?

The Junior Code Breaker Book: 50 intriguing code puzzles to crack: can you solve them all?

Secret Code Games for Clever Kids®: More than 100 secret agent and spy puzzles to boost your brainpower

Puzzles for Spies: The brand-new puzzle book from GCHQ, with a foreword from the Prince and Princess of Wales