The paratheatrical form here described as ‘Invisible Theatre’ has been little investigated by the English-speaking academic world, beyond a nod in the direction of the work of Augusto Boal. In the following article, Martin Maria Kohtes suggests that the silent interlacing of art and life in ‘Invisible Theatre’ has historical and theoretical implications which extend beyond the specifics of ‘theatre for the oppressed’ or ‘guerrilla theatre’, to call into question our understanding of what constitutes the act of theatre itself. In tracing the history of the concept back to the Weimar Republic, Kohtes develops a hypothesis to explain the visibility of ‘Invisible Theatre’ at specific historic moments – and in so doing he hopes also to illuminate for a wider audience some of the ideas and research methods of German Theaterwissenschaft. Martin Maria Kohtes, who presently lives and works in Berlin and Cologne, studied Theatre Arts at the Freie Universität Berlin, at Rutgers University in New Jersey, and at the Université de la Sorbonne Nouvelle in Paris. His study of Guerilla Theater: Theorie und Praxis des amerikanischen Strassentheaters was published by Gunter Narr Verlag, Tübingen, in 1990.