This volume contains two chapters of direct interest for applications: The magnetic vortex states and transformations and the effects of c-axis coupling on the transport properties. In addition, the isotope effect is reviewed, since reliable data on ultra-pure samples are now available. The lattice vibrations (phonons) have been explored extensively by inelastic neutron scattering and infrared absorption and these types of data are reviewed as well. The interesting properties of the superconducting doped fullerenes are described; some of their most fundamental properties are shared by the superconducting cuprates. This book with its subject index, like the earlier three volumes in this series, will be found useful both by people entering the field and by workers who are already active in it.