The historiography and social science literature on the Catholic church in Latin America since 1930 is large and unsatisfactory. There are two main reasons why it is unsatisfactory. First, most ecclesiastical archives, especially that of the Vatican, remain closed to scholars for this period. Secondly, most of the publications on the subject since the late 1960s have been written from the partisan perspectives of the Catholic Left and Catholic Right. From these have emerged two orthodoxies: the one perceiving the diffusion of a ‘theology of liberation’ as a radical break with five gloomy centuries of overidentification of the Roman Catholic church in Latin America with encrusted and oppressive power structures; the other, with equal rigidity, seeing the changes of the 1960s and 1970s as posing a grotesque challenge from within to the creative traditions of five centuries of self-abnegating missionary activity. Both of these orthodoxies are highly critical in tone; neither is self-critical in spirit. Few attempts have been made to examine the cumulative significance of the sequence of small changes in the church between 1930 and the early 1960s. No serious attempt has been made to challenge the assumption that a major transformation occurred in the church in the 1960s and 1970s, or, if it occurred, to identify and quantify in how many parishes and among how many Catholics it had a profound impact.