2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/10866Current ideas on the X-ray spectrum of Compton-thick Seyfert 2 galaxies are reviewed, and a brief description of the four presently known sources belonging to this class are given.4 pages LaTeX, using memsait.cls. To be published in the Proceedings of the conference "From micro to mega parsecs", second Italian National conference on AGNAstrophysicstext