::Huh? The work in question deals with multiple topics. Each chapter deals with a different aspect of Medieval history. There is a note telling which chapter to reference. It contains English translations of source texts, backgrounds and issues historians deal with. It's old, but it's a solid academic book and still useful. Why not actually read the source text in question and judge for yourself if its any good or not and should be on Wikipedia, if you have a problem with the quality of the work then we can discuss it in the talk page. Also you deleted more than just that book, you deleted the Poitiers book also, which is also pretty good.