"[...]movements, with F.W. Robertson; that character is simply muscle habits, with Maudsley; that the age of art is now slowly superseding the age of science, and that the artist will drive out with the professor, with the anonymous author of "Rembrandt als Erzicher";[1] that history is consciously willed movements, with Bluntschli; or that we could form no conception of force or energy in the world but for our own muscular effort; to hold that most thought involves change of muscle tension as more or less integral to it—all this shows how we have modified the antique Ciceronian conception vivere est cogitari, [To live is to think] to vivere est velle, [To live is to will] and gives us a new sense of the importance of muscular development and regimen.[2] Modern psychology thus sees in muscles organs of expression for all efferent processes. Beyond all their demonstrable functions, every change of attention and of psychic states [...]".

A General Introduction to Psychoanalysis is written by Sigismund Schlomo Freud, an Austrian neurologist remembered as the founding father of psychoanalysis for his numerous works including The Interpretation of Dreams, Three Essays on the Theory of Sexuality and Beyond the Pleasure Principle. This book contains the author’s research papers which were read in various conferences and were even rewritten by Freud. Freud‘s approach to dreams, unconscious and the theory of neuroses were part of his lectures, which had been compiled to a book form later.