Combining information from multiple sources, image fusion provides a more accurate description of a scene than any one of the individual source images alone. Using multiple modalities increases the reliability and overall performance compared to single-sensor imaging systems, as the various sensors provide complementary information about the scene. This text explores both the theoretical and applicative aspects of image fusion, illustrating its uses in concealed weapon detection, surveillance, medical diagnosis, and remote sensing, to name only a few. The authors discuss the progress of research into image fusion and highlight the way to solve practical problems using the technique. [Edit review] [Delete review]