During the last two decades, the theory of ion-atom collisions, and particularly of charge-exchange reactions, has advanced rapidly to the point where existing texts are no longer suitable as an introduction to the subject. This book aims to remedy the situation by providing an account of modern theoretical methods used to study the interaction of positive ions with atoms (or ions), concentrating particularly on charge-exchange reactions. These reactions cannot be studied in isolation, and it is necessary to consider to some extent, the whole range of ion-atom collisions leading to elastic...