The Mystery of the Flying Express (Hardy Boys Mystery Stories Book 20)

iv, 217, [1] pp. 8vo. #20 in the Hardy Boys series. Light brown boards, dark brown titles, orange Gretta endpapers, black-and-white frontispiece by Paul Laune. The same title has been used for two completely unrelated story lines. The original story (offered here) involves the 'Flying Express' railway. This railway passes close to a foreign spy camp hidden in a forest. The revised edition involves a Flying Express hydrofoil.