The Republic of the Sudan was long the largest country in Africa and, according to the general consensus, also one of the least successful in many ways. This was not entirely its fault since it lay along the fault line between Muslim and Christian Africa and between the Nile Valley civilizations and African Sudanic cultures. This partly explains the long and bloody warfare waged by the Southerners to achieve independence, which they did in July 2011. So this hefty book actually covers not one but two states. This fourth edition of the Historical Dictionary of the Sudan does so, first, through a lengthy and detailed chronology tracing its relatively few successes and numerous failures. The introductory essay does an admirable job of putting it all in perspective. But the most informative part is the dictionary, with now over 700 entries for this fourth edition. They deal with important personalities, politics, the economy, society, culture, religion and inevitably the civil war. There are also appendixes and an extensive bibliography.