With the recent advances in multimedia technology on-line libraries of digital images are assuming an ever increasing relevance within a wide range of information systems. Effective access to such archives requires on external textual keywords that conventional searching techniques based are complemented by content-based queries addressing appearing visual features of searched data. Central to this retrieval approach is the creation of models which permit to abstract images into some space of features and support indexing and comparison of visual contents. Depending on the specific characteris- tics of the images at hand such models can rely on different facets of the informative contents of visual data: color and texture distribution shape of appearing objects spatial arrangement. This book introduces and exemplifies objectives and research themes in image modeling and retrieval. In the introductory chapter the problem of image modeling and retrieval is motivated and discussed and major entry-pointers to the literature are provided. Afterwards different model- ing approaches are addressed in six chapters contributed by major research groups in the field: modeling based on object shape is addressed in chapter 2 by F. Korn N. Sidiropoulos C. Faloutsos E. Siegel and Z. Protopapas and in chapter 3 by R. Mehrotra and J. E. Gary; modeling based on color and texture distribution is addressed in chapter 4 by G. D. Finlayson S. S. Chat- terjee and B. V. Funt and in chapter 5 by I. Gagliardi A.