  Evidence in favor of supersymmetric grand unification including that based on
the observed family multiplet-structure, gauge coupling unification, neutrino
oscillations, baryogenesis, and certain intriguing features of quark-lepton
masses and mixings is noted. It is argued that attempts to understand (a) the
tiny neutrino masses (especially Delta m^2 (nu_2 -nu_3)), (b) the baryon
asymmetry of the universe (which seems to need leptogenesis), and (c) the
observed features of fermion masses such as the ratio m_b/m_tau, the smallness
of V_cb and the maximality of theta_{nu_mu-nu_tau}, seem to select out the
route to higher unification based on an effective string-unified G(224) =
SU(2)_L x SU(2)_R x SU(4)^c or SO(10)-symmetry, operative in 4D, as opposed to
other alternatives.
  A predictive framework based on an effective SO(10) or G(224) symmetry
possessing supersymmetry is presented that successfully describes the masses
and mixings of all fermions including neutrinos. It also accounts for the
observed baryon asymmetry of the universe by utilizing the process of
leptogenesis, which is natural to this framework. It is argued that a
conservative upper limit on the proton lifetime within this
SO(10)/G(224)-framework, which is so far most successful, is given by (1/3-2) x
10^34 years. This in turn strongly suggests that an improvement in the current
sensitivity by a factor of five to ten (compared to SuperK) ought to reveal
proton decay. Implications of this prediction for the next-generation nucleon
decay and neutrino-detector are noted.
