  Particle physics models with Natural Supersymmetry are characterized by a
superpotential parameter \mu \sim m_h \sim125$ GeV, while third generation
squarks have mass <0.5-1.5 TeV. Gluinos should be lighter than several TeV so
as not to destabilize the lighter squarks. First and second generation
sfermions can be at the tens-of-TeV level which yields a decoupling solution to
the SUSY flavor and CP problems. Adopting a top-down approach, we delineate the
range of GUT scale SUSY model parameters which leads to a Natural SUSY mass
spectrum. We find natural SUSY models to be tightly constrained by the b->
s\gamma branching fraction measurement while it is also difficult but not
impossible to accommodate a light Higgs scalar of mass ~125 GeV. We present
several benchmark points which are expandable to slopes and planes. Natural
SUSY is difficult to see at LHC unless some third generation squarks are very
light. The top- and bottom- squarks cascade decay mainly to higgsino-like
charginos and neutralinos via numerous possibilities, leading to a rather
complex set of signatures. Meanwhile, a linear e^+e^- collider operating at
\sqrt{s}\sim 0.25-0.5 TeV would be a higgsino factory and is essentially
guaranteed a SUSY discovery of the low-lying charged and neutral higgsino
states. Since thermal neutralino cold dark matter is underproduced, we
conjecture that the incorporation of a Peccei-Quinn sector or light moduli into
the theory will augment higgsino dark matter production, possibly together with
an admixture of axions. We present rates for direct and indirect higgsino dark
matter detection for the case where light higgsinos dominate the dark matter
abundance.
