Even in the new millenium, many astronomical objects cannot be resolved spatially with any available telescope. Most stars are too small and galaxies are too far away to be imaged directly or in detail in the foreseeable future. However, advances in data-analysis techniques allow us now to create detailed indirect images using tomographic methods. These images provide unprecedented insights into fundamental processes that drive the evolution of stars and galaxies, such as accretion and magnetic-field generation, on length scales that are of great physical importance but which are otherwise inaccessible. Here we present a collection of papers on recent progress in astrotomography, all of which were presented at Joint Discussion 09 of the XXV General Assembly of the IAU in Sydney, during July 2003. The online edition of the journal contains several illustrative movies for free download.