CIKM 2009 (ACM 18th Conference on Information and Knowledge Management ) will be held on November 2-6, 2009, Hong Kong. Since 1992, CIKM has successfully brought together leading researchers and developers from the database, information retrieval, and knowledge management communities. The purpose of the conference is to identify challenging problems facing the development of future knowledge and information systems, and to shape future research directions through the publication of high quality, applied and theoretical research findings. In CIKM 2009, we will continue the tradition of promoting collaboration among multiple areas. We encourage submissions of high quality papers on all topics in the general areas of databases, information retrieval, and knowledge management.