MARY BOWSER AND THE CIVIL WAR SPY RING

Using a provided packet of helpful tools, readers can search for clues along with a historical spy in the house of Jefferson Davis, president of the Confederacy.

Fans of ciphers and hidden clues will find both in abundance, beginning on the copyright page and continuing to a final, sealed-off section of explanations and solutions. Fictionalized but spun around actual figures and events, the tale centers on Bowser, a free African-American who worked undercover as a maid in Davis’ house and passed information to a ring of white Richmond spies. Here she looks for the key phrase that will unlock a Vigenère cipher—an alphabetic substitution code—while struggling to hide her intelligence and ability to read. As an extra challenge, she leaves the diary in which she records some of her experiences concealed for readers to discover, using allusive and sometimes-misleading clues that are hidden in Cliff’s monochrome illustrations and in cryptic marginal notations. A Caesar cipher wheel, a sheet of red acetate, and several other items in a front pocket supply an espionage starter kit that readers can use along the way; it is supplemented by quick introductions in the narrative to ciphers and codes, including Morse dashes and dots and the language of flowers.

Plenty of work for sharp eyes and active intellects in this history-based series opener.