The purpose of this study is to build a general principle for the automatic book-classification which can be put to use in library operation, and to present a methodology of the automatic classification for the library. Since the enumerative classification scheme which exist as manual systems cannot be a n.0, pplied to the automation of classification, the principles of Colon Classification by S.R. Ranganathan is brought in and studied. The result of the study can be summarized as follows: (1) Automatic book-classification can be performed by the principles of faceted classification. (2) This study presents a general and an a n.0, pplication principles for the automatic book-classification. (3) File design for the automatic book-classification of a general classification is different from that of special classification, (4) The methodology is to classify the literature by inputting the title into a terminal. In addition, the expected Value from the Automatic Book-classification is as follows: (1) The prompt and accurate process of classification is possible. (2) Though a book is classified in any library it can have the same classification number. (3) The user can retrieve the classification code of a book for which he or she wants to search through the dialogue with the computer. (4) Since the concept coordination method is employed, even the representing of a multi-subject concept is made simple. (5) By performing automatic book-classification, the automation of library operation can be completed.