Edition: Later printing.
Garden City, New York: Doubleday, n.d. (c 1930.). Hardcover - A combination of adventure, science fiction and mystery story for young adults - and a prediction of what the future of aviation might bring. Foreword by Alexander Klemin. Reprint for The Parents' Institute, Inc as a title in the 'Teen-age Mystery Classics' series, no date (only orig copyright), probably late 50's or early 60's, bound in dark blue cloth with red magnifying glass on front cover with 'Teen-age Mystery Classics' inside, red panel with title in dark blue on spine. 250 pp.
Condition: Good only (some wear to the covers, corner of front endpaper torn off.)