  Although originally conceived as primarily an extragalactic survey, the Sloan
Digital Sky Survey (SDSS-I), and its extensions SDSS-II and SDSS-III, continue
to have a major impact on our understanding of the formation and evolution of
our host galaxy, the Milky Way. The sub-survey SEGUE: Sloan Extension for
Galactic Exploration and Understanding, executed as part of SDSS-II, obtained
some 3500 square degrees of additional ugriz imaging, mostly at lower Galactic
latitudes, in order to better sample the disk systems of the Galaxy. Most
importantly, it obtained over 240,000 medium-resolution spectra for stars
selected to sample Galactocentric distances from 0.5 to 100 kpc. In combination
with stellar targets from SDSS-I, and the recently completed SEGUE-2 program,
executed as part of SDSS-III, the total sample of SDSS spectroscopy for
Galactic stars comprises some 500,000 objects.
  The development of the SEGUE Stellar Parameter Pipeline has enabled the
determination of accurate atmospheric parameter estimates for a large fraction
of these stars. Many of the stars in this data set within 5 kpc of the Sun have
sufficiently well-measured proper motions to determine their full space
motions, permitting examination of the nature of much more distant populations
represented by members that are presently passing through the solar
neighborhood. Ongoing analyses of these data are being used to draw a much
clearer picture of the nature of our galaxy, and to supply targets for detailed
high-resolution spectroscopic follow-up with the world's largest telescopes.
Here we discuss a few highlights of recently completed and ongoing
investigations with these data.
