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We simulate a plausible cosmological model in considerable physical andnumerical detail through the successive phases of reheating (at 10<z<20),formation of Pop III stars at z=15 (due to molecular hydrogen cooling), withsubsequent reionization at z=7. We assume an efficiency of high mass starformation appropriate to leave the universe, after it becomes transparent, withan ionizing background J_21=0.4 (at z=4), near (and perhaps slightly below) theobserved value. Since the same stars produce the ionizing radiation and thefirst generation of heavy elements, a mean metallicity of Z/Z_\sun=1/200 isproduced in this early phase, but there is a large variation about this mean,with the high density regions having Z/Z_\sun=1/30 and low density regionsessentially no metals.  Reionization, when it occurs, is very rapid, which will leave a signaturewhich may be detectable by very large area meter-wavelength radio instruments.Also, the background UV radiation field will show a sharp drop from 1Ryd to4Ryd due to absorption edges.  The simulated volume is too small to form L_* galaxies, but the smallerobjects which are found in the simulation obey the Faber-Jackson relation.  In order to explore theoretically this domain of "the end of the dark ages"quantitatively, numerical simulations must have a mass resolution of the orderof 10^{4.5} M_\sun} in baryons, high spatial resolution (1 kpc) to resolvestrong clumping, and allow for detailed and accurate treatment of both theradiation field and atomic/molecular physics.Comment: submitted to Ap

Reionization of the Universe and the Early Production of Metals