  We investigate the classical phase space of 2-d string theory. We derive the
linearised covariant equations for the spacetime fields by considering the most
general deformation of the energy-momentum tensor which describes $c=1$ matter
system coupled to 2-d gravity and by demanding that it respect conformal
invariance. We derive the gauge invariances of the theory, and so investigate
the classical phase space, defined as the space of all solutions to the
equations of motion modulo gauge transformations. We thus clarify the origins
of two classes of isolated states.
