Dark matter and metal abundances in elliptical galaxies from X-ray observations of the hot ISM

I review the results of recent analysis and interpretation of X-ray observations of elliptical galaxies, focusing on elemental abundances and dark matter. The hot ISM is characterized by subsolar Fe abundances and solar Si-to-Fe ratios; and, I compare these with stellar abundances and discuss implications of these measurements. From models constructed to explain X-ray temperatures and their correlation with optical properties in a complete sample of ellipticals, I demonstrate the ubiquity of dark matter in L > L-* galaxies, present limits on dark matter structural parameters, and discuss the scaling of dark halos with optical luminosity. The mass-to-light ratio within 6R(e) has a universal value, M/L-V approximate to 25h(80)M./L-V., that conflicts with the simplest extension of CDM theories of large scale structure formation to galactic scales.