Optical Properties of Early-Type Galaxies

We review the systematics of optical properties of elliptical and dwarf spheroidal galaxies. The scaling laws and correlations among the global properties of these systems can be used to deduce some information about their formation. Both dissipation and mergers appear to be important in the formation of elliptical galaxies. Small, but systematic differences between cluster and field ellipticals are detected, and also between normal ellipticals and brightest cluster members. The scaling laws for dwarf galaxies are very different from those of normal ellipticals, and point to a formation dominated by a single process