Book excerpt: This book addresses recent developments in the ecology, evolution, systematics, physiology, and biodiversity of gall-inducing arthropods, with individual contributions ranging in scope from detailed descriptions to profoundly synthetic studies. One underlying theme is the various impacts of gall induction that indirectly affect insect communities on the host plant. The other important contribution is the highly intricate and dynamic interactions between galling arthropods and their uniquely specialized host plants.