The Si(111) 7 X 7 surface is exposed at room temperature to atomic hydrogen and studied with scanning tunneling microscopy (STM) and low energy electron diffraction (LEED) in ultrahigh vacuum. For increasing exposures, the LEED pattern of the surface changes in well defined steps to a 1 X 1 pattern. The STM images of the 1 X 1 surface appear rough and disordered. The 1 X 1 pattern and rough surface are consistent with an etching;of several surface layers by the atomic hydrogen. Heating the 1 X 1 surface to 560 degrees C and cooling to room temperature produces a surface with a root 3 X root 3R30 degrees LEED pattern. The STM images of this surface are consistent with a distribution of adatoms on an ideal Si(111) surface. Further heating results in a 7 X 7 surface.