This book is aimed at the modern tectonicist who is using a vast array of "tools" from stratigraphy to petrology and isotopic techniques to interpret the geologic evolution of a study area. These tools are summarized in the introductory part of this book. The major interpretative principles in tectonics will also be summarized – e.g. calc-alkaline magmatism indicates the presence of a subduction-related arc, etc. Modern examples are then used to define the unambiguous characteristics of a tectonic setting, addressing for example what kinds of rock assemblages are found in subduction settings; these characteristics are then projected to ancient orogens. The book will also be the first to present some new tectonics concepts in a textbook format – e.g. delamination and lower crustal flow. These processes operate at regional scales and thus have to be dealt with here – they do not refute plate kinematics but rather complement it.