This paper traces the roots of the current library preservation movement and its evolution during the second half of the 20th century. It also looks at some of the contemporary shifts in thinking about preservation and changes in practice that are being explored by libraries. Finally the paper draws some conclusions as to the scope of programs in future. It suggests that a 21st century preservation program might contain the following elements: risk management and mitigation; physical treatment; copying; registration; applied research (analog and digital); digital initiatives coordination; repository and facility management; and trend analysis and strategic planning. (Author/AEF)