  The neutron, in addition to possibly having a permanent electric dipole
moment as a consequence of violation of time-reversal invariance, develops an
induced electric dipole moment in the presence of an external electric field.
We present here a unified non-relativistic description of these two phenomena,
in which the dipole moment operator, $\vec{\cal D}$, is not constrained to lie
along the spin operator. Although the expectation value of $\vec{\cal D}$ in
the neutron is less than $10^{-13}$ of the neutron radius, $r_n$, the
expectation value of $\vec {\cal D}\,^2$ is of order $r_n^2$. We determine the
spin motion in external electric and magnetic fields, as employed in past and
future searches for a permanent dipole moment, and show that the neutron
electric polarizability, although entering the neutron energy in an external
electric field, does not affect the spin motion. In a simple non-relativistic
model we show that the expectation value of the permanent dipole is, to lowest
order, proportional to the product of the time reversal-violating coupling
strength and the electric polarizability of the neutron.
