  We determine the vacuum structure and phases of N=1 theories obtained via a
mass \mu for the adjoint chiral superfield in N=2, SO(n_c) SQCD. For large
number of flavors these theories have two groups of vacua. The first exhibits
dynamical breaking of flavor symmetry \USp(2n_f) \to U(n_f) and arises as a
relevant deformation of a non-trivial superconformal theory. These are in the
confined phase. The second group, in an IR-free phase with unbroken flavor
symmetry, is produced from a Coulomb branch singularity with Seiberg's dual
gauge symmetry. In the large-\mu regime both groups of vacua are well-described
by dual quarks and mesons, and dynamical symmetry breaking in the first group
occurs via meson condensation. We follow the description of these vacua from
weak to strong coupling and demonstrate a nontrivial agreement between the
phases and the number of vacua in the two regimes. We construct the
semiclassical monopole flavor multiplets and argue that their multiplicity is
consistent with the number of N=1 vacua.
