X-rays from star-forming regions: New objects, new physics, new visions
  Star-forming regions have been the targets of X-ray observations since the dawn of satellite X-ray astronomy. The increase in sensitivity and/or spatial resolution offered by XMM-Newton and Chandra allows a dramatic improvement, both qualitative and quantitative, on our knowledge of high-energy phenomena in these regions and the underlying physical processes. We summarize here some recent developments: the Orion Nebula Cluster and its 1000+ stellar X-ray sources; Herbig-Haro objects and their high-speed shocks; protostars, brown dwarfs and their unusual magnetic activity; and the discovery of diffuse X-ray emission from HII regions, presumably related to strong winds from massive stars. The role that future X-ray missions may play in the field is already starting to be visible. 
T. Montmerle (CES/Saclay), N. Grosso (MPE), E.D. Feigelson (Penn   State) and L. Townsley (Penn State)