Some theoretical aspects of the presence of spin in proton proton elastic scattering

Some theoretical aspects on the problem of spin in proton proton elastic scattering in the range of energy starting from few GeV/c up to ISR energies are discussed.Presented at the Symposium on Hadron-Hadron Scattering at High Energies, Liblice, Czechoslovakia, June 16–21, 1975.I thank A.Martin and J.Soffer for their help in preparing this talk.