Book excerpt: Ecological and Economic Entomology is a comprehensive advanced text covering all aspects of the role of insects in natural ecosystems and their impacts on human activity. The book is divided into two sections. The first section begins with an outline of the structure, classification and importance of insects, followed by the geographical aspects of plant distribution and the complex defences plants marshal against herbivorous insects. Insect pests affecting plant roots, stem, leaf, and reproductive systems are covered in a comprehensive review. This section also covers insects that are important in medical and veterinary science, paying particular attention to those that transmit pathogens. The section concludes with the beneficial aspects of insects, especially their use in biological control, but also as soil formers and their importance in forensic science.