  We present the Data Release 12 Quasar catalog (DR12Q) from the Baryon
Oscillation Spectroscopic Survey (BOSS) of the SDSS-III. This catalog includes
all SDSS-III/BOSS objects that were spectroscopically targeted as quasar
candidates during the full survey and that are confirmed as quasars via visual
inspection of the spectra, have luminosities Mi[z=2]<-20.5 (in a LCDM cosmology
with H_0 = 70 km/s/Mpc, Omega_M = 0.3, and Omega _L=0.7), and either display at
least one emission line with a full width at half maximum (FWHM)larger than 500
km/s or, if not, have interesting/complex absorption features. The catalog also
includes previously known quasars (mostly from SDSS-I and II) that were
reobserved by BOSS. The catalog contains 297,301 quasars detected over 9,376
square degrees with robust identification and redshift measured by a
combination of principal component eigenspectra. The number of quasars with
z>2.15 is about an order of magnitude greater than the number of z>2.15 quasars
known prior to BOSS. Redshifts and FWHMs are provided for the strongest
emission lines (CIV, CIII], MgII). The catalog identifies 29,580 broad
absorption line quasars and lists their characteristics. For each object, the
catalog presents five-band (u, g, r, i, z) CCD-based photometry together with
some information on the optical morphology and the selection criteria. When
available, the catalog also provides information on the optical variability of
quasars using SDSS and PTF multi-epoch photometry. The catalog also contains
X-ray, ultraviolet, near-infrared, and radio emission properties of the
quasars, when available, from other large-area surveys. The calibrated digital
spectra, covering the wavelength region 3,600-10,500A at a spectral resolution
in the range 1,300<R<2,500, can be retrieved from the SDSS Catalog Archive
Server.
