JAMES H. VAUGHAN is Professor Emeritus of Anthropology at Indiana University. He has conducted extensive field research in the Madagali District of Nigeria. ANTHONY H. M. KIRK-GREENE was Special Lecturer in the Modern History of Africa at the University of Oxford from 1967 until his retirement in 1992. He was previously Professor of Government at Ahmadu Bello University, Nigeria, and from 1950 to 1960 served as District Officer in Nigeria, where he discovered the English text of Hamman Yaji's diary.