powerful effect on the human mind, by experimenting on himself). In the technological frontier, he describes the futuristic role of electricity in generating heat, movement and light and of instant telecommunications spanning the globe. Therefore, he apprehended the main factors which have really contributed to the 20th century society. In one passage in the book, an engineer explains to Paolo and Maria: "I believe that the speed of communications, obtained with steam and telegraph, has contributed more than all the books, all the newspapers, all the parliaments, laws, and even all religions; to destroy the criminal old order of war among peoples and to create a new moral, sane and sincere" This was a kind of morally optimistic, pre-First World War scientific utopia. Predictions Mantegazza was accurate in predicting technological developments which became a reality (or likely will be in the future). In the first three chapters he predicts the following: A keyboard-controlled private two-seat airplane with electric engines (the "acrotach", meaning something speedy in a high place), with a full electric panel with flight instruments, including compass, temperature, wind direction, flight speed and distance indicators, flying at 150 km/h; This airplane could be transformed rapidly into an electrically operated boat ("hydrotach"), by adapting a ring of inflated rubber around it; Air conditioning in all vehicles and public places; Synthetic foods made out of proteins and carbohydrates Drugs for boosting happiness, physical strength and love; A network of clean, "cosmic" energy produced in silent, compact plants ("pandynamos"), operated by a single worker, and distributed through a network of wires extending all over the world. Energy is distributed by demand, following requests transmitted by a network of "camera obscura" terminals which display white letters on a black background Artificial brains and artificial intelligence and thinking, in devices which imitate biological brains, built of artificial neural networks made of synthetic protoplasm; Movie theaters ("panopticons") which delivered all sorts of entertainment and instructional programs, by transmitting virtual reality directly to the sensory systems of spectators, including odors, movement sensation, etc.; Medical examinations using rays which rendered the whole body transparent to vision, in real time, in three dimensions (one must remember that only two years before Wilhelm Röntgen had discovered x-rays); Prebuilt houses, using liquid plastic poured over a steel structure; Five six-hour days per workweek and much spare time for entertainment and education; Credit cards and paper-based money using a global currency;