project, the debts whlch I owe for inspiration, information, encouragement and other kinds of aid are indeed very many, and my creditors cannot all be named. I wish to mention a few persons and institutions to whom I am particularly grateful. For hls very valuable and unfailing guidance and support I wish to thank Professor Andrew P. Vayda. lt was hls suggestion that directed me to conduct research in Sarawak, and hls advice and encouragement helped me throughout the many months of preparation, field research, and finally, of data analysis and writing. In preparing for field research I also received great help from Professor Derek Freeman and from Dr. George N. AppelI; I wish to thank them both. For immeasurable help in getting my field work started and successfully completed, I am very deeply indebted to the staff of the Sara wak Museum. The Museum sponsored my research in the State, but the kindness and help of many of the staff far exceeded their official duties. I particularly wish to thank Mr. Lucas Chin, the Curator, Mr. Peter Mulok Kedit, the Government Ethnologist, and Mr. Tuton Kaboy, the Research Assistant. Others of the staff to whom I owe special thanks include Messrs. Joseph Ingai, Loh Chee Yin, Robert Naen and Jameson Buau. I am also grateful to Mr. Benedict Sandin, former Curator of the Sarawak Museum, for his valuable information and advice. While in Sarawak I was aided frequently by members of other government departments, particularly by the staffs of the District Offices in Lubok Antu, Serian and Bintulu. Among the very many individuals who gave me help, I especially wish to thank Mr. Joseph Manggie, the Community Development Officer in Serian. For their valuable assistance I also thank many officers of the Forest Department of Sarawak. I wish particularly to thank Mr. Pa ui Chai, Forest Botanist, and his staff, whose insights and advice taught me far more about Sarawak's forests than just the scientific names of the plant specimens that I x Migration among the Iban brought in for identification. My thanks go also to Mr. Philip Ngau Jalong, District Forest Officer in Bintulu during the period of my research there, and to his family for their kind hospitality and for much advice which I value highly. Many members of the Agriculture Department also offered help and advice, among them I wish to thank Mr. Chin Thian Hon, the Rice Botanist. My thanks go also to members of the Medical Department, including the staffs of the Dispensary at Lubok Antu and the General Hospital in Simanggang, as weIl as to officers of the Department of Land and Survey in Kuching. For their great hospitality and support I am very grateful to Albert and Mary Kedit, to other members of their families in Kuching, Miri, and Singapore, as weIl as to other members of their household and to their many kind friends. I have missed their company and advice greatly. For their hospitality in Kuching, Simanggang and Kuala Lumpur I also wish to thank D. Leake, S. Bjorge, A. Deissinger, M. Primiani, G. Meschede, and J. Hungate. And for h...