  In the last fifteen years several techniques based on the holographic
principle have been developed for the study of the 3D local order in solids.
These methods use various particles: electrons, hard x-ray photons, gamma
photons, or neutrons to image the atoms. Although the practical realisation of
the various imaging experiments is very different, there is a common thread;
the use of inside reference points for holographic imaging. In this paper we
outline the basics of atomic resolution holography using inside reference
points, especially concentrating to the hard x-ray case. Further, we outline
the experimental requirements and what has been practically realized in the
last decade. At last we give examples of applications and future perspectives.
