  Abundance observations indicate the presence of rapid-neutron capture (i.e.,
r-process) elements in old Galactic halo and globular cluster stars. These
observations demonstrate that the earliest generations of stars in the Galaxy,
responsible for neutron-capture synthesis and the progenitors of the halo
stars, were rapidly evolving. Abundance comparisons among large numbers of
stars provide clues about the nature of neutron-capture element synthesis both
during the earliest times and throughout the history of the Galaxy. In
particular, these comparisons suggest differences in the way the heavier
(including Ba and above) and lighter neutron capture elements are synthesized
in nature. Understanding these differences will help to identify the
astrophysical site (or sites) of and conditions in the r-process. The abundance
comparisons also demonstrate a large star-to-star scatter in the
neutron-capture/iron ratios at low metallicities- which disappears with
increasing [Fe/H]- and suggests an early, chemically unmixed and inhomogeneous
Galaxy. The very recent neutron-capture element observations indicate that the
early phases of Galactic nucleosynthesis, and the associated chemical
evolution, are quite complex, with the yields from different (progenitor)
mass-range stars contributing to different chemical mixes. Stellar abundance
comparisons suggest a change from the r-process to the slow neutron capture
(i.e., s-) process at higher metallicities (and later times) in the Galaxy.
Finally, the detection of thorium and uranium in halo and globular cluster
stars offers a promising, independent age-dating technique that can put lower
limits on the age of the Galaxy and thus the Universe.
