These proceedings feature invited reviews and contributed papers, ordered in roughly the direction of increasing size scale. After a historical introduction, they progress from circumstellar matter to active galactic nuclei, and emphasis throughout is placed on the overlap between observation and th

The area of diffuse astrophysical media is enormous and ranges over circum stellar to extragalactic scales. The physical conditions can vary from cool dusty gases to collections of relativistic particles. Flows in such media are set up by en ergy and momentum injection from winds, jets and explosions. The study of these phenomena involves physics, chemistry and, inevitably, hydrodynamics. One of the most important aspects of this study is the ever increasing overlap between theory and observation. Indeed, it can be argued that the only way to really understand these complex flows which can...