  The characteristics of irradiated solar system planetary atmospheres have
been studied for decades, consequently modern planetary science benefits from
an exhaustive body of ground- and space-based data. The study of extrasolar
planetary atmospheres, by contrast, is still in its infancy and currently rests
on a few score of datapoints, mostly of the transiting planets. This short
survey aims not to review this dynamic field but rather stresses the importance
of a few theoretical concepts and processes for our understanding of exoplanet
atmospheres. Topics covered include atmospheric structure and dynamics, cloud
processes and photochemistry of planetary atmospheres. Influences on the
albedos, spectra, and colors of extrasolar planets are reviewed and caution is
urged in the interpretation of exoplanet colors.
