Lessons from Hadron Phenomenology

The main effort of our light-front community has been in the past ten years to develop new techniques for solving QCD, be it DLCQor renormalisationgroupbased methods (for review see [1]). In practice the usefulness of any procedure (which includes the question of convergence) is often determined by how well its first approximation captures the essential features of the system under consideration. This is why phenomenology can be helpful in tailoring the approximation schemes by giving us some hints of what is important for the spectra.