  The energy gap of QCD is now understood very well. There is no doubt that the
expansion in powers of the two lightest quark masses does represent a very
useful tool for the analysis of the low energy structure. Concerning the
expansion in powers of m_s, however, the current situation leaves much to be
desired. While some of the lattice results indicate, for instance, that the
violations of the Okubo-Iizuka-Zweig rule in the quark condensate and in the
decay constants are rather modest, others point in the opposite direction. I am
confident that the dust will settle soon, so that the effective coupling
constants that govern the dependence of the various quantities of physical
interest on m_s can be determined, to next-to-next-to-leading order of the
chiral expansion.
  The range of validity of ChPT can be extended by means of dispersive methods.
The properties of the physical states occurring in the spectrum of QCD below
KKbar threshold can reliably be investigated on this basis. In particular, as
shown only rather recently, general principles of quantum field theory lead to
an exact formula that expresses the mass and width of resonances in terms of
observable quantities. The formula removes the ambiguities inherent in the
analytic continuation from the real axis into the complex plane, which plagued
previous determinations of the pole positions of broad resonances.
