This book IS an attempt to review the state-of-the-art in the fields of limnology and of marine biology in the Sudan. The need for it became apparent while we were doing some joint field work in the Nile Valley and along the Red Sea coast. We feel that several reasons justify its publication. Firstly, a vast amount of information is being gathered year after year by the staff of the Hydrobiological Research U nit of the University of Khartoum, in conjunction with the faculties of Medicine and Agriculture of this university; much of this information fails to find an outlet to the scientific literature. Secondly, we did not want to restrict our book to the Nile Valley. The Nile is such a vital life artery to the Sudan that it has dominated limnological efforts in this country, to the neglect of other geographical areas. The same holds true for the field of marine biology, which lags far behind, despite the existence of a marine field laboratory at Suakin and a research institute at Port Sudan. It is hoped that both will develop considerably in the near future.
