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Inflationary cosmology -- exponential expansion of the universe at
early times -- provides a simple, observationally tested scenario
for understanding the observed flatness and homogeneity of the
universe and the seeds of structure formation. Within this broad
framework, there are diverse mechanisms for inflation and the
density perturbations, many of which make distinctive predictions
for CMB observations. The mechanism behind inflation is sensitive to
very high-energy physics, and requires input from an
ultraviolet-complete theory of gravity (such as string theory). I
will describe two particular observables of interest: a gravity wave
signature from inflation, and non-Gaussian corrections to the power
spectrum. Building on our progress stabilizing string
compactifications in recent years, I will describe two basic
mechanisms for inflation, each of which yields one of these
distinctive signatures. Falsifiable on the basis of current and
near-term planned CMB experiments which I will review, these
examples are illustrative of the growing opportunities for trying to
connect string theory with observations.
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