This book reviews the geochemical and petrological characteristics of potassic igneous rock complexes, and investigates the different tectonic settings in which these rocks occur. The authors provide an overview and classification of these rocks and elucidate the geochemical differences between barren and mineralized potassic igneous complexes. High-K rocks host a number of epithermal gold and porphyry copper-gold deposits. In recent years, there has also been growing recognition of an association of such rocks with iron-oxide copper-gold (IOCG) deposits, intrusion-related gold deposits (IRGDs) and possibly even Carlin-type gold deposits. This book is not only relevant to academic petrologists working on alkaline rocks, but also to exploration geologists prospecting for epithermal gold and/or porphyry copper-gold deposits in modern and ancient terrains. This fourth, updated and expanded edition incorporates new data and references from Africa, Australia, Brazil, China, Greece, Iran,Mongolia, North America, Russia and Turkey, including new maps and sections and new color plates of high-grade gold-copper ore from major deposits hosted by potassic igneous rocks.