  The theoretical framework of hard exclusive reactions is reviewed with
special emphasis on the Elfe project program. Perturbative QCD studies have
shown that factorization properties allow to separate well-defined non
perturbative objects which are crucial in the understanding of confinement
dynamics from perturbatively calculable hard processes. The applicability of
this factorization in a definite energy domain is controlled by some definite
statements, as the dimensional counting rules, the helicity conservation law
and the appearance of color transparency. The few data available indicate that
the Elfe parameters indeed correspond to this well defined physics.
