Petrology is the branch of geology that deals with the origin, structure, and composition of rocks. This book has been compiled for professionals as well as for advanced graduate courses in petrology. It consists of research-focused information about the current developments and applications of modern petrologic and geochemical methods for comprehending metamorphic, igneous and even sedimentary rocks. Research analyses compiled in this book provide an overview on the applications of latest petrologic methodologies to rocks of diverse origins. They represent a broad variety of settings (from Africa to Central Asia, and from South America to the Far East) as well as ages ranging from late Precambrian to late Cenozoic, and also Mesozoic/Cenozoic volcanism.