  How does the number density of early-type galaxies (E+S0) evolve with
redshift? What are their star formation histories? Do their mass density
profile and other structural properties evolve with redshift? Answering these
questions is key to understanding how E+S0s form and evolve. I review the
observational evidence on these issues, focusing on the redshift range z=0.1-1,
and compare it to the predictions of current models of galaxy formation.
