  In this lecture I present some of the new developments concerning the use of
Pade Approximants (PA's) for resumming perturbative series in QCD. It is shown
that PA's tend to reduce the renormalization scale and scheme dependence as
compared to truncated series. In particular it is proven that in the limit
where the $\beta$ function is dominated by the 1-loop contribution, there is an
exact symmetry that guarantees invariance of diagonal PA's under changing the
renormalization scale. In addition it is shown that in the large $\beta_0$
approximation diagonal PA's can be interpreted as a systematic method for
approximating the flow of momentum in Feynman diagrams. This corresponds to a
new multiple scale generalization of the Brodsky-Lepage-Mackenzie (BLM) method
to higher orders. I illustrate the method with the Bjorken sum rule and the
vacuum polarization function.
