AbstractThe possible use of a polarized proton target in the investigation of low‐energy nucleon‐nucleon interactions is reviewed. The reconstruction of the scattering matrix and verification ofP‐,T‐and isotopical invariances are briefly discussed. Possible sources and detectors of polarized particles are considered. The problem of phase‐shift analysis and nucleon‐nucleon potentials are treated in the appendices. Tables of experimental values are given for the polarization of nucleons scattered on nucleons. Experimental quantities determined from the phase‐shift analysis are given in graphs for the energies 14.5