The Formation of Early-Type Galaxies: Observations to z=1

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.