Pan-STARRS1 has carried out a set of distinct synoptic imaging sky surveys
including the $3\pi$ Steradian Survey and the Medium Deep Survey in 5 bands
($grizy_{P1}$). The mean 5$\sigma$ point source limiting sensitivities in the
stacked 3$\pi$ Steradian Survey in $grizy_{P1}$ are (23.3, 23.2, 23.1, 22.3,
21.4) respectively. The upper bound on the systematic uncertainty in the
photometric calibration across the sky is 7-12 millimag depending on the
bandpass. The systematic uncertainty of the astrometric calibration using the
Gaia frame comes from a comparison of the results with Gaia: the standard
deviation of the mean and median residuals ($ \Delta ra, \Delta dec $) are
(2.3, 1.7) milliarcsec, and (3.1, 4.8) milliarcsec respectively. The Pan-STARRS
system and the design of the PS1 surveys are described and an overview of the
resulting image and catalog data products and their basic characteristics are
described together with a summary of important results. The images, reduced
data products, and derived data products from the Pan-STARRS1 surveys are
available to the community from the Mikulski Archive for Space Telescopes
(MAST) at STScI.