1956. First Edition. 348 pages. Blue dust jacket over blue cloth boards with gilt lettering to spine. Foreword by H.T. Flint. Calculations and diagrams throughout. Binding remains firm. Crinkling to gutters. Pages are moderately tanned throughout. Boards have mild edge wear with slight rubbing to surfaces. Crushing to spine ends. Tanning to spine and edges. Gilt lettering is darkened. Unclipped jacket has light edge wear with minor tears and chipping. Mild rubbing and marking. Tanning to spine and edges.