a large reservoir of giants exists at distances and orbital periods beyond the reach of Doppler spectroscopy. Furthermore, the best theory for the orbits of the closest EGPs is that they migrated in from further out during the early phase of star and planet formation[@trilling]. This too would imply that a large pool of EGPs resides at larger separations. Indeed, it may be that the majority of stars in the solar neighborhood harbor planetary systems, that only new techniques can reveal. This is where the direct planet detection methods, most effective at large angular distances from the parent star, will come into their own.

Theoretical Atmospheres and Chemistry of EGPs {#chemistry}
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After formation, without any significant internal sources of energy, an EGP gradually cools and shrinks. Its rate of cooling can be moderated by stellar irradiation, or by hydrogen/helium phase separation when old and light[@fortney04], but is inexorable. Jupiter itself is still cooling and its total infrared plus optical luminosity is about twice the power intercepted from the Sun. The rate of cooling is a function of mass and composition, with more massive EGPs cooling more slowly. Hence, the instantaneous state of an EGP is a function of mass, 