  Exact black hole and cosmological solutions are obtained for a special
two-dimensional dilaton-spectator ($\phi-\psi$) theory of gravity. We show how
in this context any desired spacetime behaviour can be determined by an
appropriate choice of a dilaton potential function $V(\phi)$ and a ``coupling
function'' $l(\phi)$ in the action. We illustrate several black hole solutions
as examples. In particular, asymptotically flat double- and multiple- horizon
black hole solutions are obtained. One solution bears an interesting
resemblance to the $2D$ string-theoretic black hole and contains the same
thermodynamic properties; another resembles the $4D$ Reissner-Nordstrom
solution. We find two characteristic features of all the black hole solutions.
First the coupling constants in $l(\phi)$ must be set equal to constants of
integration (typically the mass). Second, the spectator field $\psi$ and its
derivative $\psi^{'}$ both diverge at any event horizon. A test particle with
``spectator charge" ({\it i.e.} one coupled either to $\psi$ or $\psi^{'}$),
will therefore encounter an infinite tidal force at the horizon or an
``infinite potential barrier'' located outside the horizon respectively. We
also compute the Hawking temperature and entropy for our solutions. In $2D$
$FRW$ cosmology, two non-singular solutions which resemble two exact solutions
in $4D$ string-motivated cosmology are obtained. In addition, we construct a
singular model which describes the $4D$ standard non-inflationary big bang
cosmology ($big-bang\rightarrow radiation\rightarrow dust$). Motivated by the
similaritiesbetween $2D$ and $4D$ gravitational field equations in $FRW$
cosmology, we briefly discuss a special $4D$ dilaton-spectator action
constructed from the bosonic part of the low energy heterotic string action and
