As we have heard from Dr Grace, a great variety of techniques have been developed in the past 9 months or so for studying the polarization of electrons. To summarize these methods briefly, they include Mott, or nuclear scattering, Moller or electronelectron scattering, the circular polarization of bremsstrahlung, and a number of methods which depend on the annihilation of positrons in flight, or the formation and annihilation of positronium. All except the Mott scattering are essentially new and the results need to be taken with a grain of salt, since in most cases there has been no assessment of systematic errors in the observations. This needs bearing in mind especially in estimating the resultant error when the observations from a number of different laboratories are collated