1 vol. 12mo softcover, Verlag P. G. Keller, Winterthur, 1962, 141 pp.
Very good copy (cover is slightly rubbed). With a small handwr. assessmennt at the end : "Esprit clair". This short but positive comment was made by prof. Georges-Henri Bousquet (1903-1978), a French academic, who was a disciple of Pareto and a friend of Joseph Schumpeter. Text in German only.