  I show that Sudakov resummation takes a transparent form if one deals with
the second logarithmic derivative of the short distance coefficient functions
for deep inelastic scattering and the Drell-Yan process. A uniquely defined
Sudakov exponent emerges, and the constant terms not included in the exponent
are conjectured to be given by the second logarithmic derivative of the
massless quark form factor. The precise framework for the implementation of the
dispersive approach to power corrections is set-up, yielding results in
agreement with infrared renormalon expectations, but which are not tied to the
single (dressed) gluon exchange approximation. Indications for a Banks-Zaks
type of perturbative fixed point in the Sudakov effective coupling at low N_f
are pointed out. Existence of a fixed point in the Sudakov coupling is argued
to imply its universality.
