As in Volume IX, the quantum fluids theme still dominates. This is reflected in articles by Fetter on vortices in superfluid 3 He, which bears both similarities and striking differences to those in superfluid 4 He, 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, Dahmand#39;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 exampl.