A simple phenomenological introduction to the physics of multi-pomeron exchange amplitudes in connection with the Abramovski-Gribov-Kancheli (AGK) cutting rules is given. The AGK cutting rules are applied to obtain qualitative and quantitative predictions on multiparticle production at high energies. On this basis, particle production in hadron-hadron scattering, photoproduction, and in particular the transition to deep-inelastic scattering is discussed.