  We argue that a class of ``non-critical superstring'' vacua is
holographically related to the (non-gravitational) theory obtained by studying
string theory on a singular Calabi-Yau manifold in the decoupling limit $g_s\to
0$. In two dimensions, adding fundamental strings at the singularity of the CY
manifold leads to conformal field theories dual to a recently constructed class
of $AdS_3$ vacua. In four dimensions, special cases of the construction
correspond to the theory on an NS5-brane wrapped around a Riemann surface.
