OverviewThe proceedings of IAU S317 offer an updated view of the stellar halos of galaxies, from the local universe to more distant systems, discussing differences and similarities among them. They review the results of ongoing large photometric and spectroscopic surveys and compare them to the predictions of new generation simulations at the forefront of our technical capabilities. Structures are analysed on both large and small scales, with attention given to the kinematical and chemical properties of their smallest and oldest components. A number of excellent reviews on state-of-the-art research, covering fields such as first stars, galactic archaeology, stellar halos in cosmological simulations, discrete constituents of stellar halos - from field, isolated stars to globular clusters and planetary nebulae - are accompanied by contributed papers presenting the results of original research by top-level specialists in the area. IAU S317 benefits researchers with interests encompassing stellar and galactic astrophysics and galaxy evolution.