As in Volume IX, the quantum fluids theme still dominates. This is reflected in articles by Fetter on vortices in superfluid 3He, which bears both similarities and striking differences to those in superfluid 4He, and by Rainer on the ab initio calculation of the transition temperatures of superconductors. In the article by Silvera and Walraven, the authors review their original experiments on spin-polarized atomic hydrogen. Finally, Dahm's article deals with charge motion in solid helium, which is not so obviously a quantum fluid, but a system in which the behaviour is a typical example of low temperature phenomena.