Dwarf spheroidal galaxies (dSphs) lie at the faint end of the galaxy luminosity function. Despite their meagre stellar content, they appear to be highly dark matter dominated at all radii, and they hence afford us the opportunity to study the distribution of dark matter on length scales of a few hundred parsecs. This talk will summarise what has been learned about the dark matter content of dSphs from recent large-scale spectroscopic surveys. I will assess the observational evidence which suggests that the Milky Way dSphs have a common dark halo mass scale and cored inner density profiles, in conflict with expectations from cosmological simulations. I will also discuss what the observed properties of dSphs can tell us about dark matter and galaxy formation more generally.