E. E. Evans-Pritchard 
Political System of the Anuak of the Anglo-Egyptian Sudan [PDF ebook] 

This description of the political system of the Anuak is part of the results of two expeditions by the author to East Africa in 1940. Although Anuak country had been visited in 1855 by the Maltese Andrea Debono and Philippe Terranuova D’Antonio and by several other European travellers thirty to forty years ago, the Italian Bottego (1897), the French missions under De Bonchamps (1897) and Faivre {1898), Wellby (l899), Austin (1900), the German Oscar Neumann (1901), and the Mac Millan Expedition (1904), practically nothing was known about the Anuak when the Government of the Anglo-Egyptian Sudan began to administer the whole of their country in 1921, this book seeks to change that.