The insect olfactory system is a highly specialized and efficient sensory mechanism that enables insects to detect and respond to chemical cues in their environment. This system primarily involves olfactory receptors located on the antennae and maxillary palps. These receptors detect volatile compounds, allowing insects to identify food sources, mates, predators, and suitable oviposition sites. Olfactory Sensory Neurons (OSNs) within the antennae transmit signals to the antennal lobe in the insect brain, where the information is processed and integrated. The antennal lobe functions similarly to the olfactory bulb in vertebrates, organizing and refining the sensory input. This processed information is then sent to higher brain centers, such as the mushroom bodies and the lateral horn, which are involved in learning, memory, and decision-making. The remarkable sensitivity and specificity of the insect olfactory system play crucial roles in their survival and ecological interactions. This book discusses the fundamentals as well as modern approaches of insect olfactory system. The various studies that are constantly contributing towards advancing technologies and evolution of the field of entomology are examined in detail. This book is a resource guide for experts as well as students.