Preservation and conservation of library artefacts and resources are important to link the previous generation of library users to the present. This will ensure continuity and progress in the library and information world. The present paper reviewed the preservation and conservation methods of library resources in the 21st century using Nigeria as a focus. The review explained the concept of preservation and conservation of library materials, identified methods of preservation and conservation of library materials, established the place of Information Communication Technology (ICT) in the preservation and conservation of library materials, and identified the constraints of preservation and conservation of library materials. The study adopted a desktop review procedure which includes the use of secondary data and findings from other empirical studies in Nigeria and abroad. The paper found that preservation is the maintenance of library information materials so that they can be closed to the original condition as much as possible, common methods preservation of library resources of clearing and dusting of library resource, Binding, Digitization, Photocopying, Lamination, Reformation, proper shelving of books to allow free flow of air, provision of enough security personnel to prevent theft and mutilation of library resources, and installation of the air conditioner in the library. ICT plays a dominant role in the preservation of library resources which is termed “digital preservation” and the major constraints identified in the preservation of library resources are inadequate to finance, inadequate Equipment/Materials, and the Problem of Infrastructural Facilities. The study concluded that the preservation and conservation of library resources are crucial to the sustenance of quality education in Nigeria. The paper recommended that school libraries should be adequately funded and ICT should be a priority in every library and there should be existing preservation policies on information resources in all school libraries in Nigeria.