This book constitutes the refereed proceedings of the joint 9th Asia-Pacific Web Conference, APWeb 2007, and the 8th International Conference on Web-Age Information Management, WAIM 2007, held in Huang Shan, China in June 2007.

The 47 revised full papers and 36 revised short papers presented together with 4 invited papers and the abstracts of 4 keynote papers were carefully reviewed and selected from a total of 554 submissions. The papers are organized in topical sections on data mining and knowledge discovery, information retrieval, P2P systems, sensor networks, spatial and temporal databases, Web mining, XML and semi-structured data, sensor networks and grids, query processing and optimization, data streams, data integration and collaborative systems, data mining and e-learning, data mining, privacy and security, as well as data mining and data streams.