Able readers who enjoy historical mysteries and examining all sides of stories will appreciate this series about unexplainable events. Each slim volume opens with an intriguing introduction before laying out known details of the “top secret” in the subsequent three chapters. Each mystery is well-researched, well-written, and fast-paced. The writing is compact and presented in an intelligent, conversational tone, with no sense that students are being talked down to. Historical background is provided for each topic, and several possible explanations are proposed. Students will relish the tantalizing notion that there are things still unknown about these top secrets. The series is stylishly designed to suggest a conspiracy is afoot: volumes’ pages are designed to resemble file folders or dossiers with tabs. Tucked inside are photos and notes with illustrated paper clips attached to some of them. Maximizing the idea of secretiveness are the words “Top Secret” looking as if they’re “stamped” in red ink appearing randomly at the beginnings of volumes, along with occasional redactions. Many captioned, color and black-and-white photos and illustrations, both contemporary and archival, lend quality support to the series.
Additionally, “Solve It” sidebars, providing information expanding on a volume’s topic, encourage students to do creative critical thinking, problem-solving, and occasional research. Another interesting special feature is a “Declassified” page which adds extra details about the featured mystery. Back matter material includes a timeline, glossary (no pronunciation guides), “Learn More” (a bibliography of books and websites) and an index. VERDICT Solid facts and intriguing content make this a good purchasing choice for school and public libraries.