The author asks why we need the History of Books and Libraries (HBL) in education for Librarianship. To answer this question develops 6 answers. 1) Because the HBL provides a general education essential to develop the librarian curriculum, when it identifies the dynamic and dialectic linking between past, present and future of modern Librarianship. 2) Because the HBL is a practical and operational knowledge to analyze and identify ways to solve problems of the librarians of the past. 3) Because the HBL allows a systematic and rational set of textual productions generated in many different historical periods. 4) Because the HBL shows that the past account of libraries is not only a locus of power but a space where ideas are expressed economic conditions in society. 5) Because the HBL points to the need to think about their enriching encounter with the History of Reading, and 6) because the HBL is the indispensable basis to support a Philosophy of Library & Information Science.