This monograph provides a systematic treatment of the abstract theory of
adjoint semigroups. After presenting the basic elementary results, the
following topics are treated in detail: The sigma (X, X )-topology,
-reflexivity, the Favard class, Hille-Yosida operators, interpolation
and extrapolation, weak -continuous semigroups, the codimension of X in
X, adjoint semigroups and the Radon-Nikodym property, tensor products of
semigroups and duality, positive semigroups and multiplication
semigroups. The major part of the material is reasonably self-contained
and is accessible to anyone with basic knowledge of semi- group theory
and Banach space theory. Most of the results are proved in detail. The
book is addressed primarily to researchers working in semigroup theory,
but in view of the "Banach space theory" flavour of many of the results,
it will also be of interest to Banach space geometers and operator
theorists.