The aim of this volume is threefold. It is intended, firstly, as a revision aid for students on Masters level degree courses in Radiation Science. These will already have received lectures at various levels of detail on most of the topics covered here. Experience has shown, however, that in preparing for examinations, especially oral examinations, students benefit from an opportunity to put details in the context of the whole. This I have tried to do by drawing attention to important connections that exist between topics treated in different chapters. These generally involve an understanding of basic interaction processes
