Final answer:
The book pair most similar to 'The Dark Game' and 'The Code Book' is 'The Puzzle Palace' and 'The Codebreakers', as both are historical analyses of cryptography and its significance.
Step-by-step explanation:
The pair of books that are similar to The Dark Game and The Code Book in terms of explaining the historical importance of codes and codebreakers is d. The Puzzle Palace and The Codebreakers. Both of these options delve into the intricacies and significance of cryptography throughout history, discussing how codes have played pivotal roles in various historical contexts, much like The Dark Game, which talks about Civil War espionage, and The Code Book, which explores the history of secret communications. Neither Cryptonomicon nor The Da Vinci Code is primarily historical, as they are works of fiction, albeit with historical and cryptological themes. The Art of Deception and Ghost in the Wires are more focused on contemporary issues of security and hacking. In contrast, The Puzzle Palace examines the National Security Agency's history, and The Codebreakers provides a comprehensive history of secret writing, making them a closer match to the subject matter of The Dark Game and The Code Book.