This chapter reviews Pierre Janet’s books on hysteria and dissociation and provides a summary of the central concepts in each of them. Historically, Janet’s considerable body of work was neglected in favour of the rising popularity and acceptance of Sigmund Freud’s psychoanalytic conceptualizations and theories. In the 1970s a change began to occur with regard to Janet. The Societe Pierre Janet in France has been reprinting his books since 1973, and subsequently the French publisher L’Harmattan has reissued most of them. Psychological Automatism, Janet’s first book in psychology, existed only in French until recently. In L’Automatisme Psychologique as well as in an earlier paper, Janet showed that such intense emotional experiences may become dissociated and then reappear in hysterical crises. In Part One of L’Etat Mental des Hystériques, The Mental Stigmata, Janet dealt with anaesthesias, amnesias, abulias, negative symptoms of disorders of movements, and modifications of the character, all of which he regarded as mental stigmata.