  Colour transparency is a cute and indispensable property of QCD as the gauge
theory of strong interaction. CT tests of QCD consist of production of the
perturbative small-sized hadronic state and measuring the strngth of its
non-perturbative diffraction nteraction in a nuclear matter. The energy
depenednce of the final- state interaction in a nuclear matter probes a
dynamical evolution from the perturbative small-sized state to the full-sized
nonperturbative hadron. QCD observables of CT experiments correspond to a novel
mechanism of scanning of hadronic wave functions from the large nonperturbative
to the small perturbative size. In these lectures, which are addressed to
experimentalists and theorists, I discuss the principle ideas of CT physics and
the physics potential of the hadron and electron facilities in the > 10 GeV
energy range. The special effort was made to present the material in the
pedagigical and self-consistent way, with an emphasis on the underlying rich
quantum-mechanical interference phenomena.
