Theory of Small Para-Hydrogen Clusters: Magic Numbers and Superfluid Sizes*

We apply the Path Integral Monte Carlo method to study the low temperature structures and superfluidity of para\-hydrogen clusters with up to 40 molecules. We find an enhanced stability at certain `` magic '' cluster sizes and sharp jumps in superfluidity for specific cluster sizes ($N>26$). Superfluidity is largely localized on the surface and coexists with clusters with solid- like core.