"Over a decade's, diligent research was devoted to a professional search for an existing thesaurus – to facilitate the classification, and processing, of all essential information on Roman Catholicism. Personal visits were made to Catholic Universities; many librarians and scholars were interviewed; extensive correspondence was exchanged with religious orders; specialized institutes were contacted; all applicable library science, and data-processing literature was analyzed. Two consistent responses emerged from the preponderance of respondents. First, 'There is no existing, broad-scope, professional-quality, Catholic-information, classification system!' Second, 'We sure need a practical, classification system to: promptly and efficiently process the overwhelming flood of incoming information; facilitate its entrance into the electronic era!' The reasons for the research and gradual development of the Thesaurus are discussed under five sub-headings: Information-processing, Broadness of application, Clarification of Catholic communication, Holiness-nurturing, Research-enhancement."