Index of Prohibited Books
Books were periodically added to the Index over the centuries until its demise in 1966. Most prohibited books, particularly in the early years were written in Italian. Surprisingly Darwin's Origin of the Species never graced the Index although his grandfather's Zoonomia did. Americans, as latecomers to the intellectual world and remote from the Vatican, generally escaped the Index. Among the few American books to make the Index was JW Draper's The History of the Conflict between Religion and Science (1874). Evolution and Dogma by Fr. John Augustine Dahm was condemned by the Congregation of the Index, but Dahm agreed to withdraw it from publication, avoiding publication in the Index
Fear of heterodoxy persists today especially among American fundamentalists. The evils of evolution and the dangers of witchcraft are widely discussed. There is great anxiety about Harry Potter books which are read by vulnerable children. (example of Harry Potter paranoia) Many fundamentalists would love to censor these books, but are conflicted by the bad reputation of censorship and deference to the Bill of Rights. Evolution on the other hand is complex and hazardous only to high school and college students. Evolution's complexity makes it remote from the populace and easily circumvented by multitudinous creationist books written for those who learn by indoctrination.
Demand for censorship will continue as long as some learn by indoctrination (as opposed learning by education). Fortunately, for all of us, most ideologically dangerous books are self-censoring by virtue of being written for intellectuals and consequently obscure to doctrinophiles.