In his published writings Sigmund Freud maintained that it was the success of Josef Breuer's treatment of the patient known as Anna O. that prepared the ground for the development of psychoanalysis. But even during Freud's lifetime rumours began to circulate suggesting that the case was not the great success that it appeared, and in light of more recent evidence most historians of psychoanalysis today regard Breuer's treatment as a failure. Some have gone so far as to claim that because Freud knew this to be so, a fraud lies at the very foundation of psychoanalysis.In a close scrutiny of the available evidence on the outcome of the case Richard Skues argues that the widely held view of it as a failure must be rejected. This new and comprehensive study of the Anna O. case history therefore has major implications for the last half century of scholarship on this most celebrated of patients.