1926. Fourteenth Impression. 328 pages. No dust jacket. Red cloth covered boards. Black and white diagrams throughout. Pages remain bright and clean with minimal tanning and foxing. Binding remains firm. Minor pen and pencil inscriptions to endpapers. Boards have heavy shelf wear with bumping and fraying to corners and crushing and fraying to spine ends. All surfaces heavily tanned, particularly spine. Some additional marks and staining to surfaces.