Theology of the Body is the topic of a series of 129 lectures given by Pope John Paul II during his Wednesday audiences in St. Peter's Square and the Paul VI Audience Hall between September 5, 1979, and November 28, 1984. It constitutes an analysis on human sexuality. The complete addresses were later compiled and expanded upon in many of John Paul's encyclicals, letters, and exhortations. In Theology of the Body, John Paul II intends to establish an adequate anthropology in which the human body reveals God. He examines man and woman before the Fall, after it, and at the resurrection of the dead. He also contemplates the sexual complementarity of man and woman. He explores the nature of marriage, celibacy and virginity, and expands on the teachings in Humanae vitae on contraception. According to author Christopher West, the central thesis of John Paul's Theology of the Body is that "the body, and it alone, is capable of making visible what is invisible: the spiritual and the divine. It was created to transfer into the visible reality of the world, the mystery hidden since time immemorial in God, and thus to be a sign of it." At present the Theology of the Body has been widely used and included in the curriculum of the Marriage Preparation Course in the Catholic dioceses of the United States. Preceding developments in the history of ideas The series of addresses were given as a reflection on the creation of man as male and female, as a sexual being. They sought to respond to certain “distorted ideas and attitudes” fundamental to the sexual revolution. Pope John Paul II addresses how the common understanding of the human body which analyzes it as a mechanism leads to objectification, that is, a loss of understanding of its intrinsic, personal meaning. Pope John Paul's thought is influenced by his earlier philosophical interests including the phenomenological approaches of Edmund Husserl and Max Scheler, and especially by the philosophical action theory of Thomas Aquinas which analyzes human acts in the context of what is done, freely chosen, and felt, while presupposing that those acts are made possible due to the substantial union of soul and matter as required by hylomorphism. Key pre-papal writings on these topics include Love and Responsibility, The Acting Person, and various papers collected in Person and Community. These themes are continued in John Paul II's theological anthropology,