What is paper document conservation? First, how are the documents to be conserved and how will they be used? Secondly, what kind of meaning does the conservation of documents as material have? By paper documents, we refer to records and data that have been published on paper in order to convey information to people. A variety of paper documents, such as books, documents, pamphlets, maps, newspapers, posters, labels, blueprints, etc., have used various papers and visual content depending upon the era and use. Paper and visual content are primarily made of organic matter. Over time, the materials degrade as a result of internal and external physical and chemical reactions. In the past, many restoration methods have been tried to stop deterioration. Improvements in science and technology have shed light on the internal degradation caused by acid paper, and also allowed more scientific analyses of the deterioration mechanism and possible counter-measures. Currently, while upholding the basic principles of conservation (recording the condition of the material and method of conservation; choosing reversible, non-destructive conservation; and respecting the importance of the original), although each treatment requires trial and error, it is necessary to advance methods of conversation based on scientific principles. With this scientific approach, and extremely delicate handling and care, the conservation of paper documents becomes possible for the first time. The critical aspect of current conservation is not the preservation of the material. Rather, in actual practice, the first consideration is what use the materials will have now and in the future, not what can be done to restore the materials. Without doubt, the “information” in the materials is useful, but is the data about the materials necessary now, or temporarily, or not at all? After considering the “use” of the materials, we can make the correct decision about the treatment, and choose from among the alternatives such as preventative treatment (storage in a suitable preservation container), avoidance treatment (minimal repair), reproduction or transfer to another medium. If treatment is carried out without such consideration, the information may become unusable, and the proper care of many other materials may be delayed, leading to the loss of great volumes of information contained within those materials. Sometimes there is the danger of excessive repair to materials with little intrinsic meaning. A great many choices are available today, now that general thinking on document preservation and technology based on scientific knowledge has a clear orientation. Collaboration among the many people concerned with the use, preservation and conservation of materials, and each person's individual knowledge and skill, will surely play an important part in the better use of the materials. Conservation is just one option after such consideration.