Gravitational lensing and stellar dynamics provide two complementary methods to probe the smooth and clumpy stellar and dark-matter mass distribution in early-type galaxies, currently already over a range of two orders of magnitude in virial mass, more than ten orders of magnidude in dynamic mass range in each galaxy (i.e. from stars, CDM substructure to massive dark-matter halos), over 0–1 in redshift, and a range of 0–100 effective radii. This makes their unification a powerful new tool in the study of the formation, structure and evolution of these massive systems. I review recent results that we obtained, based on gravitational lens systems from the Sloan Lens ACS Survey (SLACS), and outline some ongoing and future work.
