  Properties and experimental predictions of a broad class of supergravity
grand unified models possessing an $SU(5)$-type proton decay and $R$ parity are
described. Models of this type can be described in terms of four parameters at
the Gut scale in addition to those of the Standard Model i.e. $m_o$ (universal
scalar mass), $m_{1/2}$ (universal gaugino mass), $A_o$ (cubic soft breaking
parameter) and $\tan\beta=<H_2>/<H_1>$. Thus the 32 SUSY masses can be
expressed in terms of $m_o, m_{1/2}, A_o \tan\beta$ and the as yet unknown
t-quark mass $m_t$. Gut thresholds are examined and a simple model leads to
grand unification consistent with $p$-decay data when $0.114<\alpha_3
(M_z)<0.135$, in agreement with current values of $\alpha_3 (M_Z)$.Proton decay
is examined for the superheavy Higgs triplet mass $M_{H_3}<10M_G(M_G\simeq 1.5
\times10^{16}$~GeV) and squarks and gluinos lighter than 1 TeV. Throughout most
of the parameter space chargino-neutralino scaling relations are predicted to
hold: $2m_{\tilde{Z}_1}\cong m_{\tilde{W}_1}\cong m_{\tilde{Z}_2},
m_{\tilde{W}_1}\simeq(1/4)m_{\tilde{g}}$ (for $\mu>0$) or $m_{\tilde{W}_1}
\simeq(1/3)m_{\tilde{g}}$ (for $\mu<0$), while $m_{\tilde{W}_2}\cong
m_{\tilde{Z}_3}\cong m_{\tilde{Z}_4}>>m_{\tilde{Z}_1}$. Future proton decay
experiments combined with LEP2 lead to further predictions, e.g. for the entire
parameter space either proton decay should be seen at these or the$\tilde{W}_1$
seen at LEP2. Relic density constraints on the $\tilde{Z}_1$ further constrain
the parameter space e.g. so that $m_t<165$~GeV, $m_h<105$~GeV, $m_{\tilde{W}_1}
<100$~GeV and $m_{\tilde{Z}_1}<50$~GeV when $M_{H_3}/M_G < 6$. (Invited talk at
Les Rencontres de Physique de la Vallee D'Aoste}
