  This is a classical paper by Vladimir Gribov (1930-97) which has influenced
the understanding of high energy hadron collisions and deep inelastic
scattering for several decades, and is still important today. Gribov's main
assumption - that partons have limited transverse momenta - was later proved to
be satisfied in QCD, modulo logarithmic corrections. However, QCD was just
coming into existence at the time of the lecture, and Gribov used the
super-renormalizable \phi^3 theory to illustrate his points.
