The northern region of India comprising the states of Jammu and Kashmir, Himachal Pradesh, Uttarakhand, Punjab, Haryana, Delhi and Uttar Pradesh had been explored for the insect pests belonging to the order Lepidoptera through extensive and intensive field surveys. These field surveys had been conducted over different seasons on all the vegetable crop groups in the entire region so as to being out the species, population and ecological diversity. The field surveys had covered 109 localities in the entire region and throughout the length and breadth, over 49 districts in the seven states. The faunistic surveys had revealed that there are 49 species, and their diversity is enormous not only in terms of species but also their populations. It is also evident that the results of the study will be applicable not only to the northern region of India but also the whole of India and also other parts of the world. All species had been reoriented towards the salient taxonomic details along with descriptions. The study comprises of 1277 illustrations. The unique feature of the study is the integration of taxonomic aspects with field biology and ecology details.