  Crystal lattice can trap and channel particle beams along major
crystallographic directions. In a bent crystal, the channelled particles follow
the bend. This makes a basis for an elegant technique of beam steering by means
of bent channelling crystals, experimentally demonstrated from 3 MeV to 1 TeV.
This technique was strongly developed in recent studies at CERN, FNAL, IHEP,
and BNL, and can lead to interesting applications also at the LHC, such as
crystal collimation making a collider cleaner by an order of magnitude. We
review recent developments in the field and show outlook for the future.
