  Recent X-ray spectroscopy made with ASCA have shown broad, skewed iron line
emission from Seyfert-1 galaxies. The large extent of the red tail allows
probing of the innermost regions of the black hole's accretion disc. A model of
line emission has been developed and very strong evidence for the presence of a
rapidly rotating Kerr black hole has been established in the case of
MCG--6-30-15. Issues related to the observed line equivalent width and the
position/geometry of the primary source are discussed. Both the continuum and
the reflected iron line are computed, in a consistent manner, for a source
located on the axis of rotation.
