Two hundred and seventy years ago the Vatican issued an edict prohibiting Catholics from becoming Freemasons, or from taking part in the rituals and practices of Masonic lodges. Twenty-five years ago, in 1983, this ban was repeated while the present pope, Benedict xvi, was chairman of the Congregation for Doctrines of the Faith. Drastic penalties were and are prescribed. The historical and legal relationship between the Catholic Church and Freemasonry is now examined in this well-researched dissertation by Klaus Kottman, with special emphasis on Germany. He is however taken aback by the longevity and severity of these prohibitions, all the more since the ethical values preached by Freemasons seem to be admirable ones, and Freemasonry has long since lost the taint of alleged political radicalism. In addition, between 5 and 10 per cent of the 14,000 Masons in Germany are supposedly practising Catholics. Kottmann's study first outlines the history of Freemasonry, its organisational structures and its principal beliefs. He accepts the claim that Freemasonry is not a religious cult or even a substitute religion, but primarily a humanitarian society purveying strongly ethical principles. The second part of the book outlines the series of papal decrees relating to Freemasonry since 1738 and the measures decreed in the codex of canon law as established in 1917. Despite the reformist climate of the Second Vatican Council in the 1960s, and despite pleas for a more tolerant approach, or alternatively for bishops to be given permission for a local option, the Curia has maintained its rigid stance. Kottmann details the present restrictive position in canon law, which reinforces the centralist authority of the Vatican over local dioceses in this matter. In his conclusion, Kottmann points out that the historical reasons for the Vatican's negative assessment of Freemasonry are now obsolete. Instead of the Vatican imposing sweeping penalties on the faithful, Catholics should be encouraged to exercise their own consciences in deciding whether membership in a Masonic Lodge is compatible with Catholic doctrine.