First Edition, First Printing. Fine in a fine dust jacket. Rear board pocket contains extremely rare large color folding model of Dahlberg's theory. With a foreword by famed economist, Edward Alsworth Ross. An adaptation of Dahlberg's dissertation, Dahlberg is also remembered as the inventor of the Parker fountain pen. Prior owner's signature on the front free endpaper. 8vo. 252 pp. A wonderful and rare copy of this famous economic work.