This is primarily a collection of eyewitness accounts compiled by various authors. Not originally what I expected, seeing as how this was recommended to me since I had Samantha Power's "The Problem from Hell." To be fair, I find some disagreement with Mrs. Powers in some areas, but I liked her writing style nonetheless.
As for this book, it varies from author to author. The chapters pertaining to the Armenian genocide in 1915 or the Burundi genocide in the 1970's were most informative, since I had limited knowledge on both subjects. I would not call this a "go-to" book for all things relating to each episode of genocide, such as the government policies or social atmosphere that made them possible. Instead it serves as an initial springboard, allowing the reader to become more knowledgeable, so that they may go onward to discover other books more detailed.
With that, I found this enjoyable and (admittedly) fun to read. Not "fun" in accordance to the subject obviously, but war crimes and human rights abuses is a large curiousity of mine, and this book quelled that thirst for knowledge temporarily. If you already have some background with cases like Armenia, the Holocaust, Burundi, Bosnia, Rwanda, and Cambodia, then this might only supplement your knowledge rather than expand upon it. For those who are taking a political science or history course on genocide, this is a decent tool for research. I used it in my "Politics of Genocide" course my senior year of college, and it was most helpful.