From the nucleus to the quarks

Early work by A. W. Thomas and his colleagues inspired the first measurements of polarization in pion-deuteron elastic scattering. This line of research and technology developments enabled polarization experiments in electron-deuteron elastic scattering as well as the widespread use of polarized internal targets in storage rings. These ideas and techniques are now being used to study two-photon exchange effects and to make progress toward experiments that will allow for improved extractions the d/u ratio at high x.