Deterioration of books has stormed libraries, archives and museum of the world. This paper treats the problem briefly. Studies on book preservation have been performed in the United States prior to studies in other countries, while it is at the dawn in this country. Attention to the degradation of books and archives is paid little in Japan because of the wide spread of the Japanese hand-made paper until twentieth century. Japnese hand-made paper has the longevity of over 1250 years. Much results revealed that the degradation of paper was brought about by the acidity of paper.
In addition to the acid hydrolysis, the degradation mechanism of paper was reviewed in terms of the molecular structure of cellulose. Neutral sized-paper is recommended for the preservation of book.
