I will demonstrate that, contrary to expectations, early-types
galaxies contain a significant amount of cold molecular gas, and that
the spatially-resolved kinematics of this gas can be used to establish
its origin. More importantly, the molecular gas turns out to be an
excellent, arguably the best tracer of the circular velocity in
early-type galaxies, thus allowing accurate total/dynamical mass
measurements. I will exploit this principally in two ways. First, to
show that an accurate CO Tully-Fisher (luminosity-circular velocity)
relation can easily be derived for early-type galaxies. This opens the
way to probe the mass growth of galaxies of all types to significant
redshits, with a unique and simple method. Second, to show that CO can
be used to accurately measure the mass of the supermassive black holes
lurking at galaxy centres. This opens the way for literaly hundreds of
measurements across the Hubble sequence, potentially revolutionising
our understanding of the co-evolution of galaxies and black holes.