The presentation of this book to American and English readers is the result of a recent stay in Vienna, during which I had ample opportunity to observe and study the work of Professor Schilder and Dr. Kauders, at the Psychiatric Clinic.

The purpose of the book is not only to familiarize the general medical profession with the theory and practice of hypnotism, but also to present a full account of the present state of the subject as embodied both in the investigations of Professor Schilder and Dr. Kauders, as well as in those of other authorities, concerning brain function and biological reactions and their coincidence with the latest data accorded in the newer conceptions and researches of psychoanalysis.

Aside from any individual or critical opinion on the validity and foundational structure of the authors' theories and findings, one must also be impressed in reading this little book with their profound knowledge of and ready acquaintance with all the material involved in the subject at hand. Nor will it escape the reader that in spite of the authority with which their knowledge and ability permits them to speak the authors have presented their work and their expositions with due modesty and conservatism.

The translator has aimed throughout at keeping the text as far as possible in its original form. Where he has appended foot notes embodying observations of his own, intended to amplify statements in the text, he has marked them as his own in order that the reader may be aware that these notes do not constitute a portion of the German original.