  The fragile light elements lithium, beryllium, and boron are easily destroyed
in stellar interiors, and are thus superb probes of physical processes occuring
in the outer stellar layers. The light elements are also excellent tracers of
the chemical evolution of the Galaxy, and can test big bang nucleosynthesis
(BBN). These inter-related topics are reviewed with an emphasis on stellar
physics.
  In Part I (presented by CPD), an overview is given of the physical processes
which can modify the surface abundances of the light elements, with emphasis on
Population I dwarfs - convection; gravitational settling, thermal diffusion,
and radiative levitation; slow mixing induced by gravity waves or rotation. We
will discuss the increasingly large body of data which begin to enable us to
discern the relative importance of these mechanisms in Population I main
sequence stars.
  In Part II (presented by MHP), discussion is extended to the issue of whether
or not the halo Li plateau is depleted, and includes the following topics: Li
dispersion in field and globular cluster stars, Li production vs. destruction
in Li-rich halo stars, and constraints from 6Li. Also discussed are trends with
metal abundance and Teff and implications for chemical evolution and BBN.
  In Part III (presented by CC), evidence is reviewed that suggests that in
situ mixing occurs in evolved low mass Population I and Population II stars.
Theoretical mechanisms that can create such mixing are discussed, as well as
their implications in stellar yields.
