Human past is splendid and full of wonders. The past is known by records, archives, books, and other library materials which constitute the Documentary Sources. There are also other things like the monuments, buildings, art objects, and other artefacts. All these constitute the human heritage. They need conservation and preservation. Librarians, archivists, curators, chemists, and archaeologist World over are conceded with the problems of conservation and preservation. The documentary sources which are in the form of manuscripts, books, records, archives, films, CDs, etc are fragile and prone to decay and deterioration. These are damaged because of weather, fire, insects, rodents, floods, virus, and many other factors, Sometimes the documentary sources are also destroyed because of wars, holocaust, disasters, and religious animosity, and intolerance. The examples are of the burning of the great libraries at Alexandria and Nalanda in Egypt and India respectively and the recent destruction of Buddha in Afghanistan. Preservation is a part of the conservation. preservation is concerned with problems like the repair, dusting, fumigation, deacidification, air-conditioning, lamination, binding, storage, etc of manuscripts, books, films, disks, and optical materials. The principles of preservation of documentary materials in libraries, archives, and digital databases in the light of raped technological advances are to be re-examined and re-evaluated. The present title consists of 33 papers written by scholars, experienced by them in their work environments and suggested solutions. The book is useful to all types of Librarians.