This fourth volume in the series 'Physics and Chemistry of Materials
with Layered Structures' is concerned with providing a critical review
of the significant optical and electrical properties by established
authors who have themselves made many significant contributions to these
fields. Research into these materials has recently gained a new impetus
and their fascinating properties have attracted many new research
workers. These people should find much of value in the reviews contained
in this volume and the editor is very much indebted for the painstaking
and hard work put into the preparation of the various chapters by the
authors. The optical properties provide useful information for deriving
the band struc- tures, a knowledge of which is required for an
interpretation of measurements on the electronic properties. The
chapters by Dr Evans, Dr Williams and Dr Bordas describe different
techniques which have provided much detailed data on this subject. An
interesting property of these materials is the comparative ease with
which thin specimens may be prepared for these measurements and this is
highlighted in the super conducting experiments outlined by Professor
Frindt and Dr Huntley. These authors together with Dr Vandenberg's
chapter on the magnetic properties also describe the interesting and
significant intercalation mechanisms whereby a wide range of organic
compounds and alkali metals may be incorporated in the lattice. This
provides an additional parameter for varying the properties of these
materials and may yet be seen to provide eventual possible applications
of layer compounds.