  We present near-IR photometry and imaging observations of a small sample of
sources identified in the BeppoSAX 5-10 keV survey (HELLAS) which resolves ~
20-30% of the X-ray background at these energies. The near-IR data are combined
with optical spectra and photometry. Only 40% of the sources in our sample have
the blue, power law continuum typical of color-selected QSOs. The remaining 60%
are dominated by a galactic component which, on the basis of the continuum
colors and shape, have ages ranging from 10^9 to 10^10 years. The images show
that the blue QSOs are pointlike at our angular resolution, while all the other
sources are extended, consistent with their spectral appearance and low
redshift. Since down to R=20 only about two thirds of the HELLAS sources have a
counterpart, the preliminary HELLAS census comprises in roughly equal parts: i)
blue QSOs (mostly at high redshifts); ii) optically dim, galaxy-dominated
active nuclei (mostly at modest redshifts); and iii) empty fields (possibly
highly absorbed QSOs at high redshifts).
