  The origin of fermion generations is one of the great mysteries in particle
physics. We consider here a possible solution within the Standard Model
framework based on a nonabelian generalization of electric-magnetic duality.
First, nonabelian duality says that dual to the colour (electric) symmetry
SU(3), there is a ``colour magnetic symmetry'' $\widetilde{SU}(3)$, which by a
result of 't~Hooft is spontaneously broken and can thus play the role of the
"horizontal symmetry" of generations. Second, nonabelian duality suggests the
manner this symmetry is broken with frame vectors in internal symmetry space
acting as Higgs fields. As a result, mass matrices factorize leading to fermion
mass hierarchy. A calculation to first order gives mixing (CKM and MNS)
matrices in general agreement with experiment. In particular, quark mixing is
seen naturally to be weak compared with leptons, while within the lepton
sector, $\mu-\tau$ mixing turns out near maximal but $e-\tau$ mixing small,
just as seen in recent $\nu$ oscillation experiments. In addition, the scheme
leads to many testable predictions ranging from rare FCNC meson decays and
$\mu-e$ conversion in nuclei to cosmic ray air showers above $10^{20}$ eV.
