  We analyze the accelerator constraints on the parameter space of the Minimal
Supersymmetric extension of the Standard Model, comparing those now available
from LEP II and anticipating the likely sensitivity of Tevatron Run II. The
most important limits are those from searches for charginos, neutralinos and
Higgs bosons at LEP, and searches for stop squarks, charginos and neutralinos
at the Tevatron Collider. We also incorporate the constraints derived from b
--> s + gamma decay, and discuss the relevance of charge- and colour-breaking
minima in the effective potential. We combine and compare the different
constraints on the Higgs-mixing parameter mu, the gaugino-mass parameter
m_{1/2} and the scalar-mass parameter m0, incorporating radiative corrections
to the physical particle masses. We focus on the resulting limitations on
supersymmetric dark matter, assumed to be the lightest neutralino,
incorporating coannihilation effects in the calculation of the relic abundance.
We find that m_chi > 51 GeV and tan(beta) > 2.2 if all soft
supersymmetry-breaking scalar masses are universal, including those of the
Higgs bosons, and that these limits weaken to m_chi > 46 GeV and tan(beta) >
1.9 if non-universal scalar masses are allowed. Light neutralino dark matter
cannot be primarily Higgsino in composition.
