Armstrong's thesis, that the Crusades are having an impact on contemporary Middle East politics and the relations among the three Abrahamic faiths, is well-researched and convincingly argued. It is fairly easy to posit that the past has an influence on what is going on today. I would definitely agree. It is also clear that the Crusaders engaged in some behavior that would quite naturally lead to resentment, distrust and anger among the people residing in the Middle East of that time and today. However, Armstrong makes the mistake of starting at the Crusades and ignoring that which occurred prior to the Christian armies taking back the Holy Land. She mentions in passing that Muslim armies had attacked non-Muslim lands but fails to condemn these invasions at all. One glaring error I found is that she claimed that Muslims had no aggressive intentions on Europe and that the Christians had no reason to suspect or fear Muslim aggression. Tell that to the Spaniards and the Eastern Europeans and the Byzantines. Let's not even mention that the entire Muslim expansion through Arabia, the Levant, North Africa, Persia and South Asia were accomplished with the sword. If I were a Christian in Europe or anywhere else in the world, I would have feared Muslim aggression based on history and reason, not due to some misunderstanding of the Muslims. Islam was, and in some ways remains, a religion not solely of the sword but definitely one in which the sword plays a central role. Perhaps another book could be written that could posit that the entire conflict in the Middle East today is a result of Muslim imperialism in the 7th-10th centuries C.E. which was the direct cause of the Christian reaction leading to the Crusades.
Another issue with the book is Armstrong making claims about the meaning of the Quran. It is obvious from reading this book that Armstrong has not read the Quran critically or is merely trying to placate the Muslims. (Of course, writing critically about the Quran or Muhammed is a dangerous business, just ask Rushdie, and I don't really blame Armstrong for failing to be critical.) The Quran does say that war should be defensive but it also encourages, and some would say obligates, Muslims to start aggressive wars with the justification that any area that is not Muslim is hostile to Islam and therefore a threat to be dealt with. I am not a scholar of the Quran, and Armstrong knows far more than I do, but I have read it and, while it does contain some wonderful passages, it also has many contradictory passages which were recited to support the current needs of the Muslim community according to Muhammed. It is a book of peace and a book of war. It is a book of love and a book of hatred. It is a book of tolerance and intolerance, depending on one's point of view. Picking and choosing sections of the Quran to support a view can be done by both Muslim apologists defending the faith and Muslim-haters who want to bash it. Both the apologists and the bashers take things out of context, depending on how the context is interpreted. Armstrong clearly revealed her bias in how she viewed this book.
While I am not convinced that Armstrong is merely a Muslim-apologist, it is clear from the book that she does harbor some antipathy toward Christianity and tends to be far more critical of Christians than she is of Jews, and definitely Muslims. Living in the world today, we are the heirs of our past but blaming the ills on the Christian Crusaders alone is ridiculous. Perhaps it is more fair to say that the misery and oppression felt by Muslim countries in the Middle East is just as much a result of Muslim imperialist aggression against the Christian world as of Western imperialism in the Muslim world. Imperialism can be good or bad depending on which side of the equation you fall on!
But, I am not here to write history but to relate what I found in the book. In summary, it is a good thesis, well-argued, but overtly anti-Christian and overly sympathetic to early Muslim imperialism. I give it three stars for the great research and wonderful writing style.