  Determinations of the \he3 concentrations in Galactic matter serve to impose
interesting and important constraints both on cosmological models and on models
of Galactic chemical evolution. At present, observations of \he3 in the solar
system and in the interstellar medium today suggest that the \he3 abundance has
not increased significantly over the history of the Galaxy, while theoretical
models of Galactic chemical evolution (utilizing current nucleosynthesis yields
from stellar evolution and supernova models) predict a rather substantial
increase in \he3. We consider the possibility that the solar \he3 abundance may
have been affected by stellar processing in the solar neighborhood prior to the
formation of the solar system. Such a discrepancy between solar abundances and
average galactic abundances by as much as a factor of two, may be evidenced by
several isotopic anomalies. Local destruction of \he3 by a similar amount could
serve to help to reconcile the expected increase in the \he3 abundance
predicted by models of galactic chemical evolution. We find however, that the
production of heavier elements, such as oxygen, places a strong constraint on
the degree of \he3 destruction. We also explore the implications of both
alternative models of Galactic chemical evolution and the stellar yields for
\he3 in low mass stars, which can explain the history of the \he3 concentration
in the Galaxy.
