1937. First Edition. 256 pages. Paperback with blue striped paper cover. Missing dust jacket, but right flap is included. Contains some black and white graphs. Book is in better condition than most examples of this age. Neat, clean, well bound pages with very minimal foxing, tanning and thumbing. Small inscriptions and neat labels may be present. Paper cover has mild edge-wear with light rubbing and creasing. Some light marking and sunning.