Why do people in a crowd act so differently from when they are alone? What mysterious force makes individuals surrender their judgment to a leader or a mob? In Group Psychology and the Analysis of the Ego (1921), Sigmund Freud applies the insights of psychoanalysis to the psychology of crowds — drawing on Gustave Le Bon, William McDougall, and his own clinical observations to propose that group bonds are powered by erotic ties (libido) and that the leader stands in for the ego ideal of each member. This modern-English edition presents Freud’s classic in clear, contemporary language, preserving the originality of his argument while removing the barriers of archaic translation. A glossary, annotated key passages, and a reading guide help today’s reader navigate Freud’s provocative claims about suggestion, identification, hypnosis, and the primal horde — all with the critical awareness that this is a historical work, not a substitute for modern psychological science. Part of The Modern Wisdom Library.