1960. No Edition Remarks. 43 pages. Pictorial blue paperback. Contains black and white in-text illustrations. Locomotion Papers No. 13. Pages remain bright and clear with minimal tanning and foxing. Light thumb-marking present. Binding remains firm. Paper cover has light edge wear with minimal scuffing to edges and creasing. Light rubbing to surfaces with slight curling to corners. Rust staining to staple binding. Moderate sunning to spine and edges.