Mantegazza was a neurophysiologist, and when he wrote the book, impressive discoveries were being made at a quick pace around European laboratories on the organization and function of the nervous system, by scientists like Santiago Ramón y Cajal, Charles Scott Sherrington, Emil du Bois-Reymond, and where the role of axons and synapses in the transmission of information and of neural networks were being elucidated. He also acknowledged the progress of psychopharmacology in discovering new drugs which affected the emotions, conscience, cognition, etc. (Mantegazza was the first to isolate cocaine from coca leaves and to praise its 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.