Incoming Resources
- Creating and cracking codes, Lesley McFadzean
- Spy codes and ciphers, Susan K. Mitchell
- Mysterious messages, a history of codes and ciphers, Gary Blackwood ; designed and illustrated by Jason Henry
- Top secret, a handbook of codes, ciphers, and secret writing, Paul B. Janeczko ; illustrated by Jenna LaReau
- Codes, ciphers, and cartography, math goes to war, Terry Burrows
- Making secret codes, by Jillian Gregory
- Breaking secret codes, by Jillian Gregory