Entomology is an ancient science, dating back to the establishment of biology as a formal field of study by Aristotle (384-322 BC). There are even earlier references to the use of insects in daily life: such as the growing of silkworms that began 4700 BC in China, which was an important part of peasant life in China, as early as 4000 BC.This is the study of insects and their relationship to humans, the environment and other organisms. Entomologists make great contributions to such diverse fields as agriculture, chemistry, biology, human/animal health, molecular science,criminology, and forensics. The study of insects serves as the basis for developments in biological and chemical pest control, food and fiber production and storage, pharmaceuticals epidemiology, biological diversity, and a variety of other fields of science.Sufficient food production for a growing human population has become an issue of global concern. Almost all of the world’s fertile land is currently in use and arable land areas cannot be expanded significantly. The global challenge isto secure high and quality yields and to make agricultural production environmentally compatible. Insects have been hugely successful in terms of both species richness and abundance. Insects make up the most numerous groupof organisms on earth, around 66% of all animal species, and being good dispersers and exploiters of virtually all types of organic matter, can be found almost everywhere, forming an important part of every ecosystem and are vital within our food supply chains performing valuable ecosystem services. Insects have been predominantly perceived as competitors in the race for survival. Herbivorous insects damage 18% of world agricultural production.This book including the largest phylum Arthopoda. It includes the study of Taxonomy, Morphology. Physiology, Ecology, Toxicology, Biological Control, Chemical Control Integrated Pest Management etc. A number of books have already been written in entomology due to its enormous depth and diversity of this subject.So some attempts have been made in this book entitled “Entomology at a Glance “ to deliver one liner type for the competitive exams like ICAR JRF, SRF, IARI PhD, ARS- NET, different SAU exams and other comprehensive examinations. This book is written to fulfill the requirement of those studentsseeking for the above said competitive examinations in the field of entomology.