Children's mystery books are engaging stories designed for young readers that revolve around solving a puzzle or crime. These books often feature relatable characters, such as detectives or young sleuths, who embark on adventures to uncover secrets and find clues. The plots are typically age-appropriate, encouraging critical thinking and problem-solving skills. These books can vary in complexity, from simple mysteries for early readers to more intricate plots for older children. Popular series, like Nancy Drew and The Hardy Boys, have captivated generations, fostering a love for reading while stimulating curiosity and imagination in young minds.