  We discuss the Montonen-Olive electric-magnetic duality for the BPS massless
monopole clouds in N=4 supersymmetric Yang-Mills theory with non-Abelian
unbroken gauge symmetries. We argue that these low energy non-Abelian clouds
can be identified as the duals of the infrared bremsstrahlung radiation of the
non-Abelian massless particles. After we break the N=4 supersymmetry to N=1 by
adding a superpotential, or to N=0 by further adding soft breaking terms, these
non-Abelian clouds will generally condense and screen the non-Abelian charges
of the massive monopole probes. The effective mass of these dual non-Abelian
states is likely to persist as we lower the energy to the QCD scale, if all the
non-Abelian Higgs particles are massive. This can be regarded as a
manifestation of the non-Abelian dual Meissner effect above the QCD scale, and
we expect it to continuously connect with the confinement as we lower the
supersymmetry breaking scale to the QCD scale.
