Based on the information in the passage, it can be inferred that, prior to the implementation of the Dewey decimal system, A. libraries were generally small enough that no classification system was needed. B. libraries refused to make public the systems they used to classify books. C. patrons may have relied heavily on library staff to identify and locate the materials they sought. D. more people worked as librarians than after its use became widespread. E. library patrons were never able to understand the order in which books were shelved.