  Current, accumulating evidence for (mildly) relativistic blue- and
red-shifted absorption lines in AGNs is reviewed. XMM-Newton and Chandra
sensitive X-ray observations are starting to probe not only the kinematics
(velocity) but also the dynamics (accelerations) of highly ionized gas flowing
in-and-out from, likely, a few gravitational radii from the black hole. It is
thus emphasized that X-ray absorption-line spectroscopy provides new potential
to map the accretion flows near black holes, to probe the launching regions of
relativistic jets/outflows, and to quantify the cosmological feedback of AGNs.
Prospects to tackle these issues with future high energy missions are briefly
addressed.
