“The Flying Machine Boys on Duty; Or, The Clue Above the Clouds” by Frank Walton promises an exhilarating adventure that takes readers to new heights—literally. Join the Flying Machine Boys as they embark on a mission filled with intrigue and danger. Walton's storytelling soars as high as the flying machines in the narrative, making this book a thrilling choice for those who enjoy tales of bravery, mystery, and innovation.