Reading order
| # | Title | Published | Author | Buy on Amazon |
|---|---|---|---|---|
| 1 | The Secret of the Skeleton Key | 2011 | Penny Warner | N/A |
| 2 | Top Secret Code Busters Club Handbook | 2015 | Penny Warner | Buy |
| 3 | The Haunted Lighthouse | 2012 | Penny Warner | N/A |
| 4 | The Mystery of the Pirate’s Treasure | 2013 | Penny Warner | N/A |
| 5 | The Mummy’s Curse | 2014 | Penny Warner | N/A |
The Code Busters Club Non-Fiction materials extend the educational side of Penny Warner’s mystery series into standalone reference guides. The Top Secret Code Busters Club Handbook (2015) teaches young readers the actual codes and ciphers used in the fiction series, turning the books’ puzzle elements into a learning resource.
These companion materials complement the novels by giving readers the tools to practice code-breaking beyond the stories, reinforcing the series’ blend of entertainment and education.