Stodola retired at the age of 70. Then, he did not teach, but he carried on as expert and advisor. He was interested in Theoretical physics and philosophy, as well. In 1931, he published his book about philosophy of technology ‘Gedanken zu einer Weltanschauung vom Standpunktedes Ingenieurs’ (‘Thoughts of a worldview from the standpoint of the engineer’). The title of the fourth and fifth edition was "Die geheimnisvolle Naturweltanschauliche Betrachtung." It was his contribution to social, political and technological issues of his time. This book was reprinted several times and made a significant contribution to the technical philosophy in Europe.