  We discuss the main ingredients necessary to build models of chemical
evolution of spiral galaxies and in particular the Milky Way galaxy. These
ingredients include: the star formation rate, the initial mass function, the
stellar yields and the gas flows. Then we discuss models for the chemical
evolution of galaxy disks and compare their predictions with the main
observational constraints available for the Milky Way and other spirals. We
conclude that it is very likely that the disk of our Galaxy and other spirals
formed through an ``inside-out'' mechanism, where the central parts collapsed
much faster than the external ones. This mechanism has important consequences
for the appearance of galaxy disks as a function of redshift.
