This chapter presents an overview of the petrology of the Azores Archipelago, based on a review of the published literature on the mineralogy, petrology and major element geochemistry of the Azores islands and Formigas islets. In this chapter, we describe the mineralogy, petrology and major element chemistry of xenoliths/enclaves including peridotites, gabbros and syenites, and their roles in the magmatic evolution of the islands in which they occur. Where sufficient temporal data are available, we further describe the petrogenesis of the islands within a geochronological context. This synthesis and comparison of the petrology of each island is further combined with new modeling results for depth of melting and melt evolution paths to better understand the origin of the distinct petrologic characteristics of individual islands and the archipelago as a whole.