- Research associate University Nairobi, 1967-1983, University Dar es Salaam, 1974-1975, Department Education, Zanzibar, 1975-1976. Consultant World Wildlife Fund and International Union for Conservation of Nature, since 1978. Researcher Ministry of Information and Culture, Sultanate of Oman, 1978.
Author: The History of Malindi, 1973. Cargoes of the East: The Ports, Trade and Culture of The Arabian Seas and Western Indian Ocean, 1978. Zanzibar: Tradition and Revolution, 1978.
Run, Rhino, Run, 1982. Rhino Exploitation, 1983. The Japanese Ivory Industry, 1985.
Editor: African Perspectives, since 1981.