Signed by Author; 8vo - over 7¾"" - 9¾"" tall; 95 pp; First Edition. Gift dedication signed ""from the author"" and dated 1943. Former library book with many of the usual marks, pages lightly toned and unmarked, brown fabric covers with light wear to the spine end/corners. A nice, clean, tight and attractive book. Includes the original patents at the rear.