Ivan Illich (1926-2002) was one of the most original social and religious thinkers of the 20th Century. Ordained a Roman Catholic priest in 1951, he became an advocate of a "new Church" and a critic of the existing form of the Roman Church which he called "a giant that begins to totter before it collapses." The novelty of his ideas antagonized conservative forces in the Church, and he ended the controversy his advocacy had stirred up at the Vatican by announcing in 1969 that he would suspend the exercise of his priesthood and proceed, in future, "as a simple faithful Christian." There followed a sequence of five books, beginning with 1970's Celebration of Awareness, calling for "institutional revolution," or sometimes "cultural revolution." Industrial institutions, from education (Deschooling Society) to medicine (Limits to Medicine), Illich wrote, were crossing a threshold into "counter-productivity," a condition in which they would get in their own way and defeat their own purposes He also suggested that crucial personal and cultural competencies were being lost to growing professional and institutional predominance.When the institutional revolution Illich proposed did not take place, he turned to the study of history in an attempt to unearth the roots of the "certainties" that had prevented reform. In books like Shadow Work, Gender and In the Vineyard of the Text, he explored how modern civilization took shape and tried, as he once said, to "observe the emergence of those assumptions which, by going unexamined, have turned into today's certainties." (Ivan Illich in Conversation, pp. 134-135). In his last years, Illich also began to speak and write about the role of the Christian Church in the formation of the modern West, putting forward the idea that the unique features of modernity are only explainable as a perverse mutation of Christian inspiration. "When I look for the roots of modernity," he said, "I find them in the attempts of the churches to institutionalize, legitimize and manage Christian vocation" (The Rivers North of the Future, p. 48).