On balance it is a solid and readable compilation of primary and secondary sources on the subject. I liked the book and the author did a good deal of work to produce it. Unfortunately, there is a gross error right in the second paragraph of the book. Though, it is peripheral to the core material. Details of such a remote period of history are scarce, understandably so, and author stretches the book with dynamics of Islam, Christianity etc in Asia during the period. In itself a fasinating topic but NOT related to Mongol Conquests.