  The ROSAT Deep Survey in the Lockman Hole contains a complete sample of 50
X-ray sources with fluxes in the 0.5-2.0 keV band larger than 5.5E-15
erg/cm2/s. Previous work has provided optical identification of 46 of the 50
X-ray sources; over 75% of the sources are AGNs (Schmidt et al. 1998). We
present now the atlas of optical finding charts and the full description of the
spectra, including emission line properties of the optical counterparts, which
are important for the object classification. New optical/infrared observations
of three of the four unidentified sources show that one source is an AGN and
two sources with an unusually large ratio of X-ray to optical flux have
counterparts in the K'-band suggesting that they are obscured AGNs.
Furthermore, we found evidence from radio emission that the remaining
unidentified source is a powerful radio galaxy (AGN). We thus obtain a 100%
completeness. During the course of our optical identification work, we obtained
optical spectr a of 83 field galaxies, of which 67 were narrow-emission line
galaxies (NELG). We demonstrate that it is highly unlikely that a significant
number of NELG are physically associated with X-ray sources.
