The Hamburg/ESO Survey for extremely metal poor stars has
in many ways revolutionized our view of the Galactic halo.
I will review the design of the survey, and its contributions
to our view of galaxy formation and early supernovae.  I will
then focus on the metallicity distribution in the halo
and how it compares to that of the Galactic globular cluster 
system and of the dwarf spheroidal satellites.