Beacons of the early universe, Active Galactic Nuclei (AGN) are some of the most luminous objects known. AGN are produced by the accretion of infalling matter onto supermassive black holes (SMBHs) residing at the centers of galaxies. However, not all AGN can be detected at optical wavelength, since in some cases much of the accretion power is absorbed by gas and dust surrounding the SMBH. To find these AGN, astronomers must turn to hard (2-8 keV) X-rays, which can penetrate the obscuring material and hence provide a direct probe of the AGN activity. We present an analysis of deep Chandra X-ray imaging data and new optical spectroscopy to characterize the time-accretion history of roughly 300 AGN spanning 0.25 < z < 4 in the SSA22 Field.