Physical aging is an important phenomenon that occurs in all glass‐forming materials, including polymeric glass‐formers. In this article, the manifestations of physical aging and structural recovery are described, including volume recovery, enthalpy recovery, evolution of viscoelastic properties, and the effects of physical aging on failure. Controversies in the field are discussed, including rejuvenation, the temperature dependence of the relaxation time at equilibrium density, and the relative time scales for relaxation of different properties, as well as modeling of structural recovery.