Formation of Bulges

Bulges, often identified with the spheroidal component of a galaxy,have a complex pedigree. Massive bulges are generally red and old,but lower mass bulges have broader dispersions in color that may becorrelated with disk colors. This suggests different formationscenarios. I will review possible formation sequences for bulges,describe the various signatures that distinguish these scenarios, anddiscuss implications for the high redshift universe. This revised version was published online in July 2006 with corrections to the Cover Date.