Luminous X-ray sources in spiral and star-forming galaxies

For studies of discrete X-ray source populations in nearby galaxies, high spatial resolution is a key to making progress. Now, for the first time, using the Chandra X-ray observatory, we are able to study these source populations in detail for galaxies beyond M31 and our local group galaxies. Analysis of accretion-driven and supernova-related discrete sources provides a new perspective oil the evolution of galactic stellar populations, as well as giving insights into the physical mechanisms operating in individual cases. A particularly intriguing area, which we are only just beginning to address, is the nature of the most X-ray-luminous sources that are being discovered in many spiral and star-forming galaxies.