  The astounding Physics results obtained with high-energy colliders in the
last two decades owe much to an impressive progress in the understanding of the
dynamics of strong interactions. I give here a personal overview of how the
advance in QCD triggered by the Physics of hadronic final states at LEP has
been exploited for New Physics searches at the LHC. Conversely, the need for
precision calculations for LHC experiments has stimulated a huge progress in
the understanding of the all-order structure of gauge theories. These results
raise high expectations on the status of QCD at the start of a linear collider.
