  Results from BeppoSAX observations of Compton--thick Seyfert 2 galaxies are
summarized and reviewed, and their general properties derived and discussed. In
five out of the seven observed sources, the nucleus is directly visible at high
X-ray energies, where the photons penetrate absorbers with column densities in
the range 1.1-4.3x10^{24} cm-2 (in the other two sources, NGC 1068 and NGC
7674, the nucleus is instead totally obscured at all energies, implying even
larger column densities). In most sources there is unambiguous evidence of a
reflection component from optically thick, cold matter, while in two (or maybe
four) cases there is also evidence of reflection from ionized matter. For the
sources with a measured X-ray luminosity, a comparison with the infrared
luminosity is made; while in two cases (the Circinus galaxy and NGC 4945) the
IR emission appears to be dominated by starburst activity, in the other three
sources (NGC 6240, Mrk 3 and TOL 0109-383) it is likely to be dominated by
reprocessing of the UV and X-ray photons emitted by an AGN.
