Milano: Casa Editrice Sociale, 1921. Seventh edition. 12mo. Original printed wrappers; 59, (4)pp. Unopened copy in original wrappers. Expected age-toning to text; else a very well-preserved copy, Very Good or better. Text entirely in Italian. Seminal work of anarchist theory, first published in 1891; this appears to be the first edition of the work to include Luigi Fabbri's biographical foreword. All early editions are scarce, especially in North America.