We consider WZW models based on the non-semi-simple algebras that were
recently constructed as contractions of corresponding algebras for se
misimple groups. We give the explicit expression for the action of the
se models, as well as for a generalization of them, and discuss their
general properties. Furthermore we consider gauged WZW models based on
these non-semi-simple algebras and we show that they are equivalent t
o non-Abelian duality transformations on WZW actions. We also show tha
t a general non-Abelian duality transformation can be thought of as a
limiting case of the non-Abelian quotient theory of the,direct product
of the original action and the WZW action for the symmetry gauge grou
p H. In this action there is no Lagrange multiplier term that constrai
ns the gauge field strength to vanish. A particular result is that the
gauged WZW action for the coset (G(k) x H(l))/H(k+l) becomes in a cer
tain limit, involving l --> infinity, the dualized WZW action for G(k)
with respect to the subgroup H.