Elastic scattering theory

A review is given of results from proton-proton elastic scattering, concentrating on data from CERN-ISR and FNAL at large c.m. transverse momenta. The questions addressed are: Which features of the differential cross-section are due to direct channel unitarity? Are these features a reflection of a simple situation in impact parameter? What kind of predictions can be derived? It is shown that direct channel unitarity produces directly observable effects, which are properly described in terms of the inelastic overlap function. (3 refs).