THEORETICAL ISSUES OF SMALL-X PHYSICS

The perturbative QCD predictions concerning deep inelastic scattering at low x are summarized. The theoretical framework based on the leadin g log 1/x resummation and k(s) factorization theorem is described and some recent developments concerning the BFKL equation and its generali zation are discussed. The QCD expectations concerning the small x beha viour of the spin dependent structure function g(1)(x,Q(2)) are briefl y summarized and the importance of the double logarithmic terms which sum contributions containing the leading powers of alpha(s)In(2)(1/x) is emphasized. The role of studying final states in deep inelastic sca ttering for revealing the details of the underlying dynamics at low x is pointed out and some dedicated measurements, such as deep inelastic scattering accompanied by an energetic jet, the measurement of the tr ansverse energy how etc, are briefly discussed.