Please note that the content of this book primarily consists of articles available from Wikipedia or other free sources online. The Rai, also known as the Khambu (people of Khumbu region) are one of Nepal''s most ancient indigenous ethnolinguistic groups. The Rai (Khambu) belong to the Kirati group or the Kirat confederation that includes the Limbu, the Sunuwar, Yakkha Dhimal, Koche, Meche, and Hayu ethnic groups. According to Professor Dor Bahadur Bista (anthropologist, Tribhuvan University) and late Professor Suniti Kumar Chatterji (linguist and Kiratologist, Calcutta university) Kirats migrated from east via north Burma and Assam along the mid-hills (lower mountains) along with their pigs in ancient times.(ref.30,31).