The material for this thesis was collected in the company of my husband, Eric J. Miller, during twenty months of sociological field-work on the Malabar-Coast, between November 1947 and July 1949. The subject of my husband's research was "An analysis of the Hindu caste system in its interaction with the total social structure in certain parts of the Malabar coast". The data for my own work we re collected in the same villages and from many of the same informants, and our field-work necessarily involved much co-operation. Each subject is however complete in itself, and the actual compilation of field-notes and the writing have been carried out independently. My field-work was made possible by the grant of a William Wyse Studentship from Trinity College, Cambridge, and of an Anthony Wilkin Studentship from the Board of the Faculty of Archaeology and Anthropology at Cambridge. The first six months of the period were spent in Feerintalmanna, a market-town with a population of 5,000 in Walluvanad talug, South Malabar District. Here I collected data on the kinship system of the Nayars and certain other matrilineal Hindu castes, and also on the patrilineal Mappillas ( Muslims) of South Malabar. Very little of the material collected in South Malabar is presented in this thesis. My data on South Malabar Nayar kinship were, I found later, incomplete in many respects, since I had been studying Nayars in an urban setting, outside their traditional village structure. Such tentative conclusions as I was able to reach were much better substantiated by my later study of the Nayars of Cochin State, whose kinship system closely resembles that of the Nayars of South Malabar. My material on Mappilla kinship in Perintalmanna was fuller, but is not dealt with here, since the Mappillas of this area are a patrilineal people with a cultural tradition very different from that of any Hindu caste, and their kinship system falls outside the scope of this essay. I hope to record this material separately at a later date, in a comparative study of patrilineal Mappilla kinship in South Malabar and matrilineal Mappilla kinship in the North of the District. The second period of six months was spent in Pattanur, a village with a population of 1200 in Kottayam talug, North Malabar District, a Lout 80 miles northwest of Perintalmanna. Here I studied the kinship system of the Nayars and other matrilineal Hindus of North Malabar. Some of the material from Pattanur is incorporated in Part V of this paper. From Pattanur we came south again to Puthurkkara, a village of similar size in the Trichurtalug of Cochin State, about 35 miles south of Perintalmanna, and roughly in the centre of the Malayalam-speaking area. The last eight months of our stay were spent in Puthurkkara, and the material collected in a village-survey there forms the basis for Parts II and III of this thesis. Part IV deals with the kinship system of the royal lineages of Kerala, and the material for it was collected from literature and from visits to palaces of the old Malabar ruling families of Kolattiri, Vellatiri and the Zamorin of Calicut. In addition to our village-surveys my husband and I paid short visits to the town of Palghat in South Malabar District, to a few small villages in Central Travancore, and to a number of towns on the coast, including (from north to south) Payyannur, Cannanore, Tellicherry, Mahe, Calicut, Ponnani, Ernakulam, Cochin, Quilon and Trivandrum. I had hoped to spend some months on a study of Nayar kinship in Central Travamore, but illness prevented me from doing this, so that my research was confined to the northern half of Kerala. The literature on the Malabar Coast, both in Malayalam and English, is rich, but I have used very little of it in this paper. This is because I am concerned to present a picture of matrilineal kinship as it exists now under modern conditions of change, In any case the literature which deals with kinship is much scantier than that, for example, which deals with the political history of the coast. A short bibliography, of English works on Malabar, useful for the student of matrilineal kinship, is included at the end of the paper.