Second year igneous petrology is taught, in my department and many others, with a very strong emphasis on practical work. The undergraduates spend several hours every week developing their microscope skills, making observations of rocks and thin sections, and identifying minerals, describing textures and attempting to infer how the rock was formed and in what kind of setting. This should and does form the basis for teaching igneous petrology. And here is a textbook that reflects this logical order! The chapters are laid out largely in terms of rock types, including chapters headed basalts, gabbros, ultramafic rocks, andesites, dacites and rhyolites, granites, and the alkali rocks, with a couple of extra chapters on magma differentiation and physical volcanology. The petrological ‘tools of the trade’ are introduced when needed, inserted into boxes separate from the main text. This layout will make sense to an undergraduate, who should make observation of rocks first and foremost, then start thinking about where the rock comes from and how it was formed.

What I really like about this book is that the relatively ‘dry’ topics (from an undergraduate's point of view) such as phase equilibria and isotope geochemistry, are introduced when they are needed in order to interpret a rock. In this way, the student will see their practical use very easily and will understand why it is important to know, for example, the phase rule and how eutectics and resorptional points differ and how these essential tools can be used to interpret the petrological history of a magma. The book assumes a certain amount of prior knowledge of basic microscope skills and mineral identification, as is appropriate for a second year text. The book does not pretend to be a ‘one-stop shop’ for the second year course. There are areas that it does not cover in great detail and for these the students must be referred to other sources. Phase diagrams are introduced and used throughout the book to interpret petrological features of rocks but some of the fundamental thermodynamics must be found elsewhere. The optical indicatrix and other practical microscopy tools are covered in detail in an appendix (again, assuming a basic prior knowledge).

As an example of how this book works, the andesites, dacites and rhyolites chapter starts with a description of mineralogy and texture, then classification. It introduces the alkali feldspar solid solution series with reference to a ternary phase diagram to aid identification and understanding of feldspars. Phase equilibria involving hydrous minerals are introduced, explaining why we often see hornblende in andesites. There follows a description of steep-sided lava flows and domes, and then a discussion of the controls on magma viscosity and the importance of volatiles and degassing for crystallisation. The origin of the calc-alkaline and low/high K trends are discussed and finally, the different tectonic settings in which silicic volcanic rocks might be found, with reference to their distinctive geochemical signatures. In other words, observations first, interpretation last. This textbook will be an invaluable guide for undergraduates in the laboratory and will allow them to develop their interpretative skills in petrology in the most intuitive way. The breadth of topics, clear layout and level of detail will no doubt lead it to become an essential, always-on-hand reference for students.