  In the first contribution the basic problems posed by the existence of the
Fundamental Plane (FP), and its relations with the Virial Theorem are
discussed. Various possibilities are presented that can produce the observed
uniform departure from homology and/or from a constant stellar mass-to-light
ratio. The role of orbital anisotropy and its relation with the FP thickness
are also discussed. In the second contribution the observational evidence for
the existence of a FP for galaxy clusters, analogous to that of ellipticals, is
presented and discussed. In the third contribution the dynamical properties of
$R^{1/m}$ spherical galaxies with variable orbital anisotropy are discussed.
The stability of the models against radial--orbit instability is studied, and
the consequences on the FP tilt and thickness are discussed. An innovative tool
for the construction of Evolutionary Synthesis models of Stellar Populations is
described in the fourth contribution. As an illustrative example, the evolution
of the stellar mass-to-light ratios has been computed and the implications on
the FP of elliptical galaxies are briefly discussed. Finally, in the fifth
contribution, with the aid of the first large sample of X-ray emitting
early-type galaxies with known kinematics, the effect of rotation on the X-ray
emission, particularly with regard to the X-ray underluminosity of flat systems
is discussed. The role of structural parameters as the ellipticity, the
isophotal shape parameter $a_4/a$, and the inner slope of the surface
brightness profile recently measured by HST are also investigated.
