Self-hypnosis or auto-hypnosis (as distinct from hetero-hypnosis) is a form, a process, or the result of a self-induced hypnotic state. Frequently, self-hypnosis is used as a vehicle to enhance the efficacy of self-suggestion; and, in such cases, the subject 'plays the dual role of suggester and suggestee'. The nature of the auto-suggestive practice may be, at one extreme, 'concentrative', wherein 'all attention is so totally focused on that everything else is kept out of awareness' and, at the other, 'inclusive', wherein subjects 'allow all kinds of thoughts, emotions, memories, and the like to drift into their consciousness'. From their extensive investigations, Erika Fromm and Stephen Kahn (1990) identified significant and distinctive differences between the application of the wide variety of practices that lie within the domain commonly, equivocally, and ambiguously identified as 'self-hypnosis'. Based upon their distinctions, 'self-hypnosis' practices can be separated into, at least, thirteen different types: The English term 'hypnotism' was introduced in 1841 by the Scottish physician and surgeon James Braid. According to Braid, he first employed 'self-hypnotism' (as he elsewhere refers to it) two years after discovering hypnotism, first teaching it to his clients before employing it on himself: In a later work, Observations on Trance or Human Hybernation (1850), Braid provides probably the first account of self-hypnosis by someone using hypnotism upon themselves: Émile Coué was one of the most influential figures in the subsequent development of self-hypnosis. His method of 'conscious autosuggestion' became an internationally renowned self-help system at the start of the 20th century. Although Coué distanced himself from the concept of 'hypnosis', he sometimes referred to what he was doing as self-hypnosis, as did his followers such as Charles Baudouin. Modern hypnotherapists regard Coué as part of their own field. Autogenic training is a relaxation technique developed by the German psychiatrist Johannes Schultz and first published in 1932. Schultz based his approach on the work of the German hypnotist Oskar Vogt. The technique involves a step-by-step progression that begins from physiological conditioning, such as muscle relaxation, breathing control and heart rate control. Then it advances to psychic conditioning through mental imagery, acoustic therapy, etc.