This book is an effort to give simple, concise and updated information about the aspect relevant to entomology. This book deals with modern concepts of entomology, which include introduction to entomology, morphology of insects, introduction to insect biodiversity, digestive system of insect, insect ecology, the tracheal system, excretory system in insects, understanding of the evolution of insects, insect pest and its management and sericulture. Related terms have been provided at the end for the ready reference of readers. This book is highly useful for graduate and post-graduate levels, teachers and researchers in entomology, pest control advisors, professional entomologists, pesticide industry managers, policy planners, and others having interest in mites and ticks.