Basic tasks in library management include the planning of acquisitions (which materials the library should acquire, by purchase or otherwise), library classification of acquired materials, preservation of materials (especially rare and fragile archival materials such as manuscripts), the deaccessioning of materials, patron borrowing of materials, and developing and administering library computer systems. More long-term issues include the planning of the construction of new libraries or extensions to existing ones, and the development and implementation of outreach services and reading-enhancement services (such as adult literacy and children's programming). Library materials like books, magazines, periodicals, CDs, etc. are managed by Dewey Decimal Classification Theory and modified Dewey Decimal Classification Theory is more practical reliable system for library materials management.