This chapter focuses on emerging aspects of polarization optics that bring new impetus to established principles and proven technologies. It first reviews the formalism of polarization and mode. There are two aspects to the discussion presented in the chapter. One involves a polarization component, and the other a spatial mode component. The chapter discusses states of polarization, spatial modes, and the combined spatial-polarization mode. It also covers the methods of production of singular beams and discusses the studies of polarization singularities. Polarization singularities hold much promise in optical diagnosis, as a technique where singularities become sensitive probes of perturbations to the wave field. On the fundamental side, work on polarization effects in three dimensions has only started and holds promise of more interesting developments.