  BeppoSAX observed the Seyfert 1 galaxy NGC 3783 for ~ 5 days from 1998 June 6
to 1998 June 10. The average flux during the observation was F(2-10 keV) ~ 6 X
10^{-11} erg cm^-2 s^-1. The long exposure provided a very high quality
spectrum that exhibits all the typical features of Seyfert 1s. The high energy
cut-off of the intrinsic continuum, at E_c=340+560/-107 keV, was detected for
the first time in this object. During the observation the source showed modest
flux variations (~ 20% in 2-10 keV) and spectral variability that can be
completely explained by a change of the intrinsic slope \Delta\Gamma ~ 0.1. NGC
3783 is one of the few Seyfert 1s that exhibits a soft emission component in
the BeppoSAX spectrum. This soft excess is well reproduced by a black body
component with temperature kT ~ 0.2 keV. A warm absorber is also required to
fit the soft X-ray spectrum. Both reprocessing features, the Compton reflection
hump and the Fe emission line, were detected in our observation. In addition to
a narrow iron line (as observed by Chandra) a broad component with sigma=0.72
+1.28/-0.27 keV and EW=115+/-76 eV, is required to fit the line. The observed
Compton hump and the Fe line are well reproduced with the ionized
(lg(xi)=2.73+0.04/-0.05) disc reflection model of Ross & Fabian. In this case
the soft excess observed below 2 keV can be accounted for by the disc
emissivity and no additional soft X-rays component is required to fit the
spectrum.
