The deterioration of books and other paper-based records is discussed. Reasons are given why machine made papers generally deteriorate more readily than earlier hand made papers. While bleaching methods have improved in regard to paper permanence, sizing continues to be a problem. The isolation of cellulose from wood launched the paper industry. Cheaper paper, made largely from groundwood pulp, is weak and deteriorates rapidly. Various accelerated ageing experiments are discussed. The damage caused by acidic additives and oxidized cellulose additives is described, as is that caused by air pollution, ozone and light. The stability of various inks is discussed. Leather is also plagued by acid from within and poor storage conditions. The control of environment for storage, use and exhibit is most important in paper preservation. Different deacidification methods are discussed as are various methods for reinforcing brittle paper, including lamination and encapsulation. Several methods of making copies of documents for use are described.