The history of theatre in the twentieth century distinguishes two theatre reforms. The first took place from the final years of the nineteenth century into the late 1930s. The second was from the mid-1950s to the late 1980s. These were movements of renewal and modernization of the art of theatre. Started by individual artists and small groups and assisted by playwrights and theorists – who were often the artists themselves – both reforms gradually reached wider areas of theatre life. The Second Reform was a reformist movement of young, avant-garde, rebellious and experimental theatre in a searching state. The movement originated in the 1950s in Poland within student and alternative theatres as well as in the United States, as Off-Broadway and then Off-Off-Broadway. It reached tremendous level of expression in the 1960s through the work of Jerzy Grotowski’s Laboratory Theatre, Bread and Puppet Theater, Living Theatre and several other companies in many countries all around the world. It matured in the 1970s, bringing out the theatre of Tadeusz Kantor. In the 1980s, it resulted in Włodzimierz Staniewski’s “Gardzienice.” However, it did not reach some areas of theatre at all. Throughout the West, in South America, Australia and in Japan, the Second Reform was a challenge and an alternative to commercial, popular and traditional theatre. In the part of Europe that was under Soviet Union’s control, the Second Reform was a challenge to totalitarian regimes; it undermined totalitarian censorship and disregarded the communist iron curtain. Its productions were manifestations of freedom. In the field of performance’s creation, the Second Reform brought out and accentuated the communality and processuality of theatre art. In the field of directing, the Second Reform decisively placed the director at the head of the team of creators preparing and executing a theatrical performance. In the field of acting, the Second Reform introduced “acting of being” in place of “acting of character.” In the aspect of space, the Second Reform sought out to integrate the playing area and the observation area of the show; its lasting achievement became a theatre with variable space, “the black box.” In the field of literature, the Second Reform questioned the underlying function of drama in the theatre, practiced “writing on stage” as well as “creating” the text of the show by the actors themselves, and “adapting” existing dramas by the director. The author of this article witnessed, chronicled and participated in the Second Theater Reform. He created productions in its spirit and wrote about it.