In analytical chemistry there is a constant interplay between techniques, theory and practice. Sometimes a technique finds instant application to long-standing problems, sometimes it may be developed and then lie fallow. In some areas of analysis electron spectroscopy has proven of immense value, but there is also a potential within the technique for solving problems, which are not at present formulated as requests for analysis. The present book address itself-sufficient. Every concept has been demonstrated by simple diagrams using simple mathematics and elegant style. The order of the techniques included in this book is conventional and would be liked by students.