  A quantity that promises to reveal important information on perturbative and
non-perturbative QCD dynamics is the azimuthal decorrelation between jets in
different hard processes. In order to access this information fixed-order NLO
predictions need to be supplemented by resummation of logarithmic terms which
are large in the region where the jets are nearly back-to-back in azimuth. In
the present letter we carry out this resummation to next-to--leading
logarithmic accuracy explaining the important role played by the recombination
scheme in general resummations for such jet observables.
