  There is a subtle difference between the open string dynamics determined by
the original dual resonance models and that determined by D-brane constructions
within critical closed string theory. For instance, in contrast to the former,
the latter have massless scalars in addition to the massless gluon shared by
both. We introduce and explain the concept of nonabelian D-branes which
illuminates this distinction. We employ this concept to offer new possibilities
for string duals for large N QCD (pure Yang-Mills gauge theory).
