  We examine the low energy structure of N=1 supersymmetric SO(10) gauge theory
with matter chiral superfields in N_Q spinor and N_f vector representations. We
construct a dual to this model based upon an SU(N_f+2N_Q-7) x Sp(2N_Q-2) gauge
group without utilizing deconfinement methods. This product theory generalizes
all previously known Pouliot-type duals to SO(N_c) models with spinor and
vector matter. It also yields large numbers of new dual pairs along various
flat directions. The dual description of the SO(10) theory satisfies multiple
consistency checks including an intricate renormalization group flow analysis
which links it with Seiberg's duality transformations. We discuss its
implications for building grand unified theories that contain all Standard
Model fields as composite degrees of freedom.
