How I Became a Spy A Mystery of WWII London by Deborah Hopkinson

This World War II London mystery plunges readers into the foggy, blacked-out streets where thirteen-year-old Bertie Bradshaw stumbles into a world of espionage and coded messages. When a young woman vanishes, leaving behind a cryptic notebook, Bertie teams up with an American girl named Eleanor to practice surveillance and hunt for a traitor, transforming their wartime survival into a high-stakes puzzle. The narrative masterfully blends historical details of the Blitz with the classic structure of a whodunit, inviting middle-grade readers to decipher clues right alongside the young sleuths.

Hopinson excels at making history feel immediate and personal, framing global conflict through the lens of a friendship where roles are constantly debated, much like Holmes and Watson. The book is a standout for its educational value, seamlessly integrating the real-life workings of British intelligence and cipher-breaking without ever slowing the propulsive plot. Young history buffs and mystery lovers alike will be captivated by this tale of ordinary children doing extraordinary things, leaving them with a profound sense of how courage and quick thinking can change the course of events.