This petrology book provides an integrated treatment of those parts of the subject that use the polarizing microscope as the central analytical tool. Part A serves as a concise but comprehensive petrography that deals with rock classification and terminology. It follows the IUGS recommendations for igneous rocks and sets out a similar hierarchical system for metamorphic rocks. Part B deals with the nature of crystallization, recrystallization, and the origin of textures, and is divided into three sections. The first deals with general principles and features such as twinning, zoning and intergrowths, found in a wide range of rocks. The second deals specifically with volcanic and plutonic textures, the third with metamorphic textures. Full reference is made to the recent literature on these topics. Part C is a discussion of the mechanisms of mineral preferred orientation development and includes a summary of laboratory methods of description and analysis. Igneous and metamorphic rocks are treated separately. Familiarity with the polirizing microscope and optical mineralogy is assumed. Otherwise the book is written for all levels, and the author's hope is that sutdents use it first as a basic petrography and subsequently as a text that guides them into the research literature as they become curious about the nature and origin of textures and rock fabrics.