1. A Brief History of Cryptography from Caesar to Bletchley Park, Simon Singh
2. How It Began: Bletchley Park Goes to War, Michael Smith
3. The German Tunny Machine, Jack Copeland
4. Colossus, Codebreaking, and the Digital Age, Stephen Budiansky
5. Machine Against Machine, Jack Copeland
6. D-Day at Bletchley Park, Thomas H. Flowers
7. Intercept!, Jack Copeland
8. Colossus, Thomas H. Flowers
9. Colossus and the Rise of the Modern Computer, Jack Copeland
10. The PC-User's Guide to Colossus, Benjamin Wells
11. Of Men and Machines, Brian Randell
12. The Colossus Rebuild, Tony Sale
13. Mr Newman's Section, Jack Copeland, with Catherine Caughey, Dorothy Du Boisson, Eleanor Ireland, Ken Myers, and Norman Thurlow
14. Max Newman-Mathematician, Codebreaker and Computer Pioneer, William Newman
15. Living with Fish: Breaking Tunny in the Newmanry and the Testery, Peter Hilton
16. From Hut 8 to the Newmanry, Jack Good
17. Codebreaking and Colossus, Donald Michie
18. Major Tester's Section, Jerry Roberts
19. Setter and Breaker, Roy Jenkins
20. An ATS Girl in the Testery, Helen Currie
21. The Testery and the Breaking of Fish, Peter Edgerley
22. Dollis Hill at War, Jack Copeland, with David Bolam, Harry Fensom, Gil Hayward, and Norman Thurlow
23. The British Tunny Machine, Gil Hayward
24. How Colossus was Built and Operated-One of Its Engineers Reveals Its Secrets, Harry Fensom
25. Bletchley Park's Sturgeon-The Fish That Laid No Eggs, Frode Weierud
26. Geheimschreiber Traffic and Swedish Wartime Intelligence, Craig McKay
A1. Timeline: The Breaking of Tunny
A2. The Teleprinter Alphabet, Jack Copeland
A3. The Tunny Addition Square, Jack Copeland
A4. My Work at Bletchley Park, Bill Tutte
A5. The Tiltman Break, Friedrich Bauer
A6. Turingery, Jack Copeland
A7. Dc-Method, Max Newman
A8. Newman's Theorem, Friedrich Bauer
A9. Rectangling, Frank Carter
A10. The Motor Wheels and Limitations, Jack Good, Donald Michie, and Geoffrey Timms
A11. Motorless Tunny, Jack Good and Donald Michie
A12. Origin of the Fish Cypher Machines, Friedrich Bauer