Everything to know about secret codes and encrypted messages, including Semaphore and Morse code, 'Grid code' used in the American Civil War, Egyptian hieroglyphics and traditional number replacement and alphabet switching. Ages: 6+.

Emily Bone grew up among the rolling hills of Hampshire, writing stories about the ants and birds in her garden. After studying English at Cambridge, she found her dream job at Usborne in 2007. Since then, she's written about many weird and wonderful creatures, along with books on space, fashion and food.