  We point out some advantages of making observations of extrasolar planets in
linearly polarized (LP) light. Older cool stars have quite low levels (~ 10^-4
to 10^-5) of fractional LP, while extrasolar planets can have relatively high
fractional LP (~0.1). Observations in LP light can therefore significantly
enhance contrast between the planet and its parent star. Data on LP as a
function of planetary orbital phase can be used to diagnose the properties
(e.g., composition, size, and shape) of the scatterers in the planetary
atmosphere. We discuss the feasibility of LP observations of extrasolar
planets.
