2023 International Summer School on the ISM of Galaxies

The unique angular resolutions that can be achieved in the Milky Way made it a prime object of studies of the interplay between stellar formation and the interstellar medium. The main challenge is here to understand the effect of the galactic environment which is difficult to characterize due to our position inside the Milky Way. The huge improvements in sensitivity and angular resolution of the current generation of observatories are delivering a large number of high quality images and spectra of the interstellar medium in nearby galaxies. This not only delivers an outsider view on the way the interstellar medium interacts with the stellar populations, but it also gives us access to a much wider diversity of physical conditions (metallicity, star formation efficiency, etc). We believe that we should motivate the new generation of astronomers, as well as the older ones, to consider ISMology as a field where, depending on the scientific question they want to answer, they can rely either on studies of galaxies or of Galactic regions. This brings several outstanding questions, such as: - How can we apply our knowledge of the Galactic ISM to other galaxies? What are the limitations? - How peculiar is the ISM of the Milky Way? How representative are nearby systems to understand the cosmic evolution of galaxies? - Which new concepts (observations, models) are required to bridge the remaining gap in angular resolution between the Milky Way and external galaxies?