This thesis is the first full-length study of the experiments in performer training undertaken by Alessandro Fersen in his studio laboratory in Rome between 1957 and 1983 and practiced since then in the codified technique which he calls Mizemodrama ( literally, "a drama of memory"). The purpose of my research is twofold: firstly, to focus on the development of the core technique of mnemodrama which is a theatrical simulation of ritual object manipulation employed by shamans in traditional cultures in order to induce an altered state of consciousness. In Fersen's terms such transic techniques provide the contemporary performer with a psychic training which enables him to explore different aspects of his persona rediscovered from both the autobiographical and archetypal levels of his unconscious. Secondly, the thesis presents a case for viewing Alessandro Fersen as a pioneer of post-war experimental theatre practice, particularly from the standpoint of the interdisciplinary nature of his experiments (theatre combined with anthropology, ethnology and psychology) and his focus on training rather than performance within the confines of a laboratory. The philosophy behind his research, its goals and methodology are therefore compared with those of his more celebrated peers, Jerzy Grotowski, Peter Brook, Richard Schechner and Eugenio Barba. This thesis combines academic research with two periods of observation of the mnemodrama in performance at Fersen's studio in Rome in 1990 and 1992. Subsequently, I was able to introduce Fersen and his work to British academic theatre professionals for the first time at the international conference on Performance, Ritual and Shamanism organised by the Centre for Performance Research and held in Cardiff in January 1993. Finally, the appendices contain Fersen's essential justification for his research, from which the arguments of this thesis have been developed. The appendices also represent the first substantial translation of Fersen's writings on theatre to appear in the English language.