  These lectures are the review of the main ideas and approaches to the
structure of the Pomeron. They are divided in three natural parts:
  (i) the brief review of the Reggeon Calculus, which was the first attempt to
build the effective theory of the strong interaction at high energy. In spite
of the fact that this approach turns out to be inconsistent and in lectures we
show why, the Reggeon approach was and is the main source of the terminology
and phenomenology for high energy ``soft" interactions.
  (ii) the detail description of the QCD approach to high energy interaction.
We try to combine the rigorous approach in perturbative QCD with more simple,
intuitive guess based on general properties of QCD to clarify our expectations
and predictions.
  (iii) the outline of my personal opinion what problems will be important in
the future.
  The main reason for the lectures was just the last part to agitate you to
think about this difficult but because of that interesting problem. The motto
of my lectures is {\it `` there is nothing more exciting than to solve a
difficult problem. Pomeron is the one.''}
