This study analyzed the difference between the two situations to verify the effectiveness of the book selection by the subject professionals in a academic library. In this, some circulation statistics before and after introduction to subject specialists were compared. Moreover, by using Minitab and t-test, ANOVA among other statistical techniques, 186,435 books selected 3 years before September 2005 and after 3 years and 622,213 circulation statistics about those books in 'S' University Library were compared and analysed. The results were as follows:(1) After introduction to the subject librarian, the proportion of books selected by librarians were increased. (2) After introduction to subject reference librarian, the foreign books selected by the faculty and the librarians were statistically significantly increased. (3) By academic field, the academic fields of the books selected by the faculty were significantly increased, but the academic fields of the books selected by the students were significantly decreased.