  The Baryon Oscillation Spectroscopic Survey (BOSS), part of the Sloan Digital
Sky Survey (SDSS) III project, has provided the largest survey of galaxy
redshifts available to date, in terms of both the number of galaxy redshifts
measured by a single survey, and the effective cosmological volume covered. Key
to analysing the clustering of these data to provide cosmological measurements
is understanding the detailed properties of this sample. Potential issues
include variations in the target catalogue caused by changes either in the
targeting algorithm or properties of the data used, the pattern of
spectroscopic observations, the spatial distribution of targets for which
redshifts were not obtained, and variations in the target sky density due to
observational systematics. We document here the target selection algorithms
used to create the galaxy samples that comprise BOSS. We also present the
algorithms used to create large scale structure catalogues for the final Data
Release (DR12) samples and the associated random catalogues that quantify the
survey mask. The algorithms are an evolution of those used by the BOSS team to
construct catalogues from earlier data, and have been designed to accurately
quantify the galaxy sample. The code used, designated MKSAMPLE, is released
with this paper.
