  We investigate the electromagnetic Casimir interactions of an object
contained within an otherwise empty, perfectly conducting spherical shell. For
a small object we present analytical calculations of the force, which is
directed away from the center of the cavity, and the torque, which tends to
align the object opposite to the preferred alignment outside the cavity. For a
perfectly conducting sphere as the interior object, we compute the corrections
to the proximity force approximation (PFA) numerically. In both cases the
results for the interior configuration match smoothly onto those for the
corresponding exterior configuration.
