  The High-Altitude Water Cherenkov (HAWC) Observatory was completed and began
full opera- tion on March 20, 2015. The detector consists of an array of 300
water tanks, each containing 200 ktons of purified water and instrumented with
4 PMTs. Located at an elevation of 4100m a.s.l. near the Sierra Negra volcano
in central Mexico, HAWC has a threshold for gamma-ray detection well below 1
TeV and a sensitivity to TeV-scale gamma-ray sources an order of magnitude
better than previous air-shower arrays. The detector operates 24 hours/day and
observes the overhead sky (2 sr), making it an ideal survey instrument. We
describe the configuration of HAWC with an emphasis on how the design was
optimized, describe the data acquired, reconstructed and an- alyzed. Finally,
we will demonstrate the sensitivity of the detector using the observation of
the Crab. This paper serves as a detailed technical description of the
foundations of the numerous analyses presented at this meeting by members of
the HAWC collaboration.
