https://www.abebooks.com/Codebreakers-Kahn-Sphere/31797862142/bd
The Codebreakers by Kahn: Very Good Soft cover (1977) | Bargain Books
Soft cover - Sphere - 1977 - Condition: Very Good - 1977 Sphere UK publication, copy is VG+ condition. Unmarked, gently read by evidence of spine wear and rubs...
the codebreakersvery goodsoft coverkahn