After reading this book, you will laugh at newspaper reports that describe the conflict in Sudan as between "the Muslim north and Christian and animist south". Johnson not only has extensive academic publications in Sudanese ethnography and historiography, but also worked in the aid field in the country. He is also, in a well-sourced, calm and clearly presented manner, outraged at how thoroughly misunderstood the situation in Sudan is. The detail in this book is amazing. I consider myself fairly knowledgeable in an armchair kind of way about southern Sudan, and was consistently being presented with either facts of which I was unaware or, better yet, syntheses tying together various fields in a historical perspective. The offensives, famines, factionalism within southern groups, agricultural schemes, external mediators, forced displacement patterns, and competing aid agencies are all here, and presented so one can see the linkages. This is one of the rare books in which, for example, the connection between the timing of government offensives to seasonal rainfall is convincingly fit within framework of underdevelopment as a political strategy.
There are a couple points that made me consider moving this down to four stars. One is that Johnson is clearly partisan to the south. He is not fatally so in my opinion, describing some very unflattering characteristics and actions of Garang's faction, and making his bias clear from the beginning. By the end of the book, he also makes a strong case that "neutrality" has been misused or abused in the context of the Sudanese wars, and led me to muse that his outrage seems to spring from his knowledge, versus some writers about southern Sudan whose outrage impedes their learning. I also occasionally found the division of the book in its latter section into thematic sections confusing, especially in cases where the text would refer to later chapters for more information about a mentioned event or process. Fortunately, the appendix includes both a detailed chronology from 1972 through 2001 and a pretty good topical index for when I needed a bit of help orienting myself. The extensive annotated bibliography would be quite useful for some people. There is also the rather obvious issue that the book was written prior to the finalization of the peace agreement and death of Garang, which makes me anxious for an update.
Bottom line: If you want to know about the conflicts in Sudan between 1983 and 2001, then this is the book. If you've read other works on Sudan, you'll be astonished at how thoroughly Johnson annihilates the common wisdom. And whoever you are, you may come to share some of Johnson's outrage.