  At the dawn of the first discovery of exoplanets orbiting sun-like stars in
the mid-1990s, few believed that observations of exoplanet atmospheres would
ever be possible. After the 2002 Hubble Space Telescope detection of a
transiting exoplanet atmosphere, many skeptics discounted it as a one-object,
one-method success. Nevertheless, the field is now firmly established, with
over two dozen exoplanet atmospheres observed today. Hot Jupiters are the type
of exoplanet currently most amenable to study. Highlights include: detection of
molecular spectral features; observation of day-night temperature gradients;
and constraints on vertical atmospheric structure. Atmospheres of giant planets
far from their host stars are also being studied with direct imaging. The
ultimate exoplanet goal is to answer the enigmatic and ancient question, "Are
we alone?" via detection of atmospheric biosignatures. Two exciting prospects
are the immediate focus on transiting super Earths orbiting in the habitable
zone of M-dwarfs, and ultimately the spaceborne direct imaging of true Earth
analogs.
