  The highlights of studies of mixing among scalar mesons below and above 1 GeV
within a nonlinear chiral Lagrangian framework is briefly presented. Two scalar
meson nonets are introduced to explore the mass spectrum and decay properties
of the $I$=1/2 and $I$=1 scalar states. For the $I$=0 states, in addition to
these two nonets a scalar glueball component is also taken into account, and
together with the constraints from the $I$=1/2 and $I$=1 sectors, their mass
spectrum is studied. The fact that an ideally mixed $q {\bar q}$ scalar nonet
has a mass ordering which is opposite to that of an ideally mixed four-quark
scalar nonet is exploited to gain some insight into the quark substructure of
the $I$=1/2, $I$=1 and $I$=0 states below and above 1 GeV. Consequently,
numerical estimates of various components of these states (two quark and four
quark components of $I$=1/2 and $I$=1 states, and two quark, four quark and
glue component of $I$=0 states) are determined.
