As the growing number of conference proceedings, preprints, periodicals and popular journal articles are being joined by various electronic forms of dissemination of research, the series Progress in Low Temperature Physics assumes a particular responsibility in providing excellent reviews, guiding the reading of the literature and providing direction for future research possibilities. In this most recent volume, the main theme is research on superfluid and adsorbed phases of helium.In five chapters the following topics are dealt with. Chapter one is a review of one of the essential characteristics of superfluid 4He, the Landau critical velocity. Chapter two reviews the amazing properties of coherent spin dynamics in superfluid 3He. The next chapter examines a unique situation with a number of thermodynamic transitions between superfluid states and discusses the current experimental and theoretical situation. Properties of phases of 3He adsorbed on graphite are discussed in the following chapter, and in a complementary final chapter a review is presented on the properties of multilayer 3He-4He mixture films.

As the growing number of conference proceedings, preprints, periodicals and popular journal articles are being joined by various electronic forms of dissemination of research, the series Progress in Low Temperature Physics assumes a particular responsibility in providing excellent reviews, guiding the reading of the literature and providing direction for future research possibilities. In this most recent volume, the main theme is research on superfluid and adsorbed phases of helium.In five chapters the following topics are dealt with. Chapter one is a review of one of the essential characteristics of superfluid 4He, the Landau critical velocity. Chapter two reviews the amazing properties of coherent spin dynamics in superfluid 3He. The next chapter examines a unique situation with a number of thermodynamic transitions between superfluid states and discusses the current experimental and theoretical situation. Properties of phases of 3He adsorbed on graphite are discussed in the following chapter, and in a complementary final chapter a review is presented on the properties of multilayer 3He-4He mixture films.