  As shown in hep-th/9709081, non-BPS saturated solitons play an important role
in the duality transformations of N=1 supersymmetric gauge theories. In
particular, a massive spinor in an SO(N) gauge theory with massless matter in
the vector representation appears in the dual description as a magnetic
monopole with a Z_2 charge. This claim is supported by numerous tests,
including detailed matching of flavor quantum numbers. This fact makes it
possible to test the phase of an SO(N) gauge theory using massive spinors as a
probe. It is thereby shown explicitly that the free magnetic phase which
appears in supersymmetric theories is a non-confining phase. A fully
non-abelian version of the Dual Meissner effect is also exhibited, in which the
monopoles are confined by non-BPS string solitons with Z_2 charges.
