  We try to gain an understanding of the recent Superkamiokande data on
neutrino oscillations and several other important phenomenological issues
within the framework of supersymmetric $SU(4)_c \times SU(2)_L \times SU(2)_R$
($\equiv G_{422}$). By supplementing $G_{422}$ with a U(1)-${\cal R}$ symmetry,
we can provide an explanation of the magnitude $M_G$ ($\sim 10^{16}$ GeV) of
the $G_{422}$- symmetry breaking scale, resolve the MSSM $\mu $ problem, and
understand why proton decay has not been seen ($\tau_p \gg 10^{34}$ yr). The
family dependent ${\cal R}$ - symmetry also helps provide an explanation of the
charged fermion mass hierarchies as well as the magnitudes of the CKM matrix
elements. Several additional heavy states in the mass range $10^4-10^7$ GeV are
predicted, and the MSSM parameter $\tan \beta $ turns out to be of order unity.
The atmospheric neutrino problem is explained through $\nu_{\mu}-\nu_{\tau}$
mixing with $\sin^2 2\theta_{\mu \tau}\simeq 1$. The resolution of the solar
neutrino puzzle is via the small angle MSW oscillations and necessarily
requires a sterile neutrino $\nu_s$ which, thanks to the ${\cal R}$ - symmetry,
has a tiny mass.
