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When I was asked to review this book I immediately pulled out my copy of the first edition, published by Thorpe and Brown in 1985, for comparison. The differences in content are representative of the advances that have taken place in igneous petrology in 26 years. The inclusion of eye-pleasing colour photographs and figures throughout the book also signifies the changes that have occurred in book publications over the years and is a pleasant departure from the black and white photographs of the first edition. Maybe the most noticeable and useful feature that has been retained is its pocket-size, which enables the user to carry the book into the field, the purpose for which the first edition and the entire field guide series were designed.

The book is divided into ten chapters, two less than the first edition, yet composed of more pages (238 vs 154). The sequencing of the chapters follows a logical approach with the exception of Chapter 10, the last, which, while useful, seems to be somewhat of an afterthought. The opening or introductory chapter provides an outline of subject material to be covered, in greater detail, in the succeeding chapters. Chapters 2 and 3 emphasize the importance of field observations. Chapter 2 highlights fieldwork skills that should be applied when working with igneous outcrops, stressing the importance in obtaining good field notes, while Chapter 3 provides a guide for the proper description and classification of igneous rocks in hand specimens collected at outcrop sites. Chapters 4 to 8 concentrate on the mode of occurrence of igneous rocks, with Chapters 4 and 5 covering lava flows and pyroclastic rocks, respectively. Unlike the first edition, where lava flows and pyroclastic rocks were confined to one chapter, these two important topics have been expanded. Shallow level intrusions are covered in Chapter 6, while deeper seated complexes such as granitic intrusions and mafic and ultramafic bodies are described in Chapters 7 and 8, respectively. A major departure from the first edition is the last two chapters, on magma mixing and mingling, and mineralization and geotechnical properties. In Chapter 9 the emphasis is mostly on magma mingling, and the field features and textures associated with such a phenomenon. Chapter 10 is devoted to the types of mineralization that occur in igneous rocks of different composition and the geotechnical properties associated with igneous rocks.

The book is well written and structured, and is easy to read even for the amateur geologist. The photos and diagrams are clear, and represent well chosen examples. At the end of most chapters the authors provide a very useful summary section accompanied either by tables or an array of colour photos that are relevant to the chapter. The only detraction is the several typographical errors that occur throughout the text. Despite this blemish, the book is an essential text for all undergraduate students of geology. A second edition of The Field Description of Igneous Rocks has been long overdue, and the authors are to be commended for reproducing an excellent and comprehensively revised version.