The book is a sequel to Thompson's 1994 The Coevolutionary Process, and picks up where the previous one left off (the majority of references in the new book are post-1994). The first part of the book begins with a discussion of the attribute of species that provide the raw material for long-term coevolution on constantly changing landscapes. Species tend to be phylogenetically conservative in the way they interact with other species. Yet, each species is a collection of genetically-differentiated populations that specialize their interactions on only a few other locally important species, so that the outcome of interactions differ from locality to locality. These are the fundamental species attributes that fuel the dynamic spatial mosaic of coevolution. This first half of the book then goes on to explore the role of local adaptation in maintaining the mosaic, present an overview of the mosaic theory of coevolution, and summarize the forms of evidence indicating that interactions are coevolving. The second part of the book evaluates the various hypotheses and predictions set within the context of the geographical mosaic of coevolution. Here the parasitologists will encounter familiar concepts such as gene-for-gene coevolution, frequency-dependent selection and the Red Queen hypothesis. Finally, the book ends with a chapter on applied coevolutionary biology. This is a call to arms, an appeal to ecologists and evolutionary biologists to apply coevolutionary thinking to the major environmental problems faced by society, including loss of biodiversity and the emergence of new pathogens.

So what is in this book for parasitologists? The very intimate nature of the host-parasite association makes it an excellent candidate for coevolutionary studies. Disappointingly, there are relatively few empirical examples drawn from the literature on classical host-parasite interactions. Other types of interactions are better-represented, such as the associations between phytophagous insects and their plant hosts. But this is only a reflection of the author's background and expertize, and it does not detract from the important message of the book. Indeed, at the conceptual level, the geographical mosaic theory of coevolution has a lot to offer to parasitologists. It provides a comprehensive framework for the study of host-parasite interactions. Local populations of a parasite species each interact with different host communities and different sets of competing parasite species, under different environmental conditions, and yet remain linked within a metapopulation structure. This spatial variation in coevolutionary circumstances across a parasite's geographical range can only yield different local outcomes in the evolution of parasite virulence or host resistance. Thompson proposes a research programme designed specifically to tackle this spatial variation. I highly recommend his book as inspirational reading for all practicing parasitologists and advanced graduate students.