  I review basic forces on moduli that lead to their stabilization, for example
in the supercritical and KKLT models of de Sitter space in string theory, as
well as an $AdS_4\times S^3\times S^3$ model I include which is not published
elsewhere. These forces come from the classical dilaton tadpole in generic
dimensionality, internal curvature, fluxes, and branes and orientifolds as well
as non-perturbative effects. The resulting (A)dS solutions of string theory
make detailed predictions for microphysical entropy, whose leading behavior we
exhibit on the Coulomb branch of the system. Finally, I briefly review recent
developments concerning the role of velocity-dependent effects in the dynamics
of moduli. These lecture notes are based on material presented at various
stages in the 1999 TASI, 2002 PiTP, 2003 TASI, and 2003 ISS schools.
