  The BeppoSAX High Energy Large Area Survey (HELLAS) has surveyed about 85
deg^2 of sky in the 5-10 keV band down to a flux of 4-5 10^-14 erg cm-2 s-1.
The source surface density of 16.9+-6.4 deg$^{-2}$ at the survey limit
corresponds to a resolved fraction of the 5-10 keV X-ray background (XRB) of
the order of 20-30 %. Hardness ratios analysis indicates that the spectra of a
substantial fraction of the HELLAS sources (at least one third) are harder than
a alpha_E = 0.6 power law. This hardness may be due to large absorbing columns.
The hardness ratio analysis also indicates that many HELLAS sources may have a
spectrum more complex than a single absorbed power law. A soft component,
superimposed to a strongly cut-off power law, is likely to be present in
several sources.
