The Twentieth Century Encyclopedia of Catholicism is a series of 150 volumes examining topics pertaining to Catholicism, many of them originally published in France. It was published in English in the United States by Hawthorn Books from 1958 to 1971. The series editor was Henri Daniel-Rops. The series was divided into 16 sections. In the United States, volumes were published individually over a number of years and made available for sale separately.