  Although studied for many years the nature of the light scalar mesons remains
controversial. Here we shall present a method, applicable for s-wave states
located close to a threshold, that allows one to quantify the molecular part of
a given state. When applied to the $f_0(980)$ a dominance of the molecular
component is found. In the second part we show that requirements of field
theoretic consistency and chiral symmetry, when applied to the scattering of
light pseudo--scalars, naturally lead to the appearance of dynamical poles in
the scalar sector. A program is proposed on how to further investigate
experimentally the mixing between these dynamical states and possible genuine
quark states.
