In "The Boxcar Children Guide to Adventure," Gertrude Chandler Warner introduces readers to creative problem-solving techniques used by young sleuths. One clever method involves writing a decoder key onto a scarf, allowing spies to carry essential information discreetly. Tying the scarf around their hair or neck keeps this vital clue hidden from anyone who might notice.

This guide not only provides mystery-solving strategies but also includes various DIY projects to engage young readers. Warner's work encourages children to use their imagination and resourcefulness in adventurous ways, making it a fun and educational experience.