  After reviewing the basic physics of X-ray reflection in AGN, we present
three case studies which illustrate the current state of X-ray reflection
studies. For the low-luminosity AGN NGC4258, we find that the iron line is much
narrower than is typically found in higher luminosity AGN. We argue that this
is evidence for either a truncated cold accretion disk (possibly due to a
transition to an advection dominate accretion flow at r ~ 100GM/c^2) or a large
r ~ 100GM/c^2 X-ray emitting corona surrounding the accretion disk. We also
present results for the higher luminosity Seyfert nuclei in NGC5548 and
MCG-6-30-15. In both of these sources, RXTE shows that the iron line equivalent
width decreases with increasing luminosity. Furthermore, the iron line
equivalent width is found to be anticorrelated with the relative strength of
the reflection continuum, contrary to all simple reflection models. It is
proposed that continuum-flux correlated changes in the ionization of the
accretion disk surface can explain this spectral variability. Finally, we
address the issue of X-ray iron line reverberation in the light of these
complicating factors.
