Multimedia data mining, as the name suggests, presumably is a combination of the two emerging areas: multimedia and data mining. However, multimedia data mining is not a research area that just simply combines the research of multimedia and data mining together. Instead, the multimedia data mining research focuses on the theme of merging multimedia and data mining research together to exploit the synergy between the two areas to promote the understanding and to advance the development of the knowledge discovery in multimedia data. Consequently, multimedia data mining exhibits itself as a unique and distinct research area that synergistically relies on the state-of-the-art research in multimedia and data mining but at the same time fundamentally differs from either multimedia or data mining or a simple combination of the two areas.