  Accreting black holes often show iron line emission in their X-ray spectra.
When this line emission is very broad or variable then it is likely to
originate from close to the black hole. The theory and observations of such
broad and variable iron lines are briefly reviewed here. In order for a clear
broad line to be found, one or more of the following have to occur: high iron
abundance, dense disk surface and minimal complex absorption. Several excellent
examples are found from observations of Seyfert galaxies and Galactic Black
Holes. In some cases there is strong evidence that the black hole is rapidly
spinning. Further examples are expected as more long observations are made with
XMM-Newton, Chandra and Suzaku. The X-ray spectra show evidence for the strong
gravitational redshifts and light bending expected around black holes.
