PART 1

So I hadn't heard of this new book on the crusades before your post (given that it's not by an academic publisher), so I decided to look into it and I regret my curiosity. The kindest thing I can say is that I didn't immediately spot any plagiarism.

Dodgy Historiography

The biggest flaw is one of simple bias; the author sees the crusaders as his side and believes that critics of crusaders were wrong at best and part of a conspiracy against the Catholic Church at worst. In particular, he believes the history of the crusades has been warped by malicious Protestant history:

"It is also important to learn Church history in order to defend the Church against its critics. The accepted historical narrative presented in the English-speaking world is centered on a predominantly Protestant perspective. This perspective is not amenable to an authentic understanding of Catholic history. As a result, most Catholics throughout their educational careers are provided an English Protestant interpretation of historical events that warps and dismisses the Catholic story. It is the necessary work of Catholic historians to undo the false aspects of this Protestant view as well as provide an authentic Catholic narrative in order to assist the faithful in defending the Church."

He follows this up by attempting to argue that the Catholic Church stands by the crusades as a historical phenomenon even though this is not the position of the papacy, and has a particular issue with Pope John Paul II's efforts to resolve historic tensions that arose as a result of the crusades, especially the Fourth Crusade. He pretends to speak for all "serious scholars", and as a serious scholar myself I found that quite funny because the author of this book is fringe at best and a hack at worst. This section of the book displays a remarkably inconsistent understanding of the historiography of the crusades. For example, he has a decent understanding of what early works on the crusades have been influential, like Runciman's three volume history and Carl Erdmann's 1935 book The Origins of the Idea of Crusading. But once we get to recent historiography (especially anything produced in the 21st century), his understanding falls apart. He claims that it's great, but only talked about Jonathan Riley-Smith, who was the credible historian most sympathetic to the crusaders. He does not mention the more cynical and less romanticised views of historians like Jonathan Phillips, Steve Tibble, John France, Jason Roche, and especially Christopher Tyerman. The author clearly has read work by these historians, because they appear in the footnotes where they are used to cite basic facts. On this basis, I think he omits them from his historiographical introduction deliberately. He is relying on the reader's own lack of knowledge of crusade historiography to present his own as authoritative, even though it certainly is not and barely refers to the most influential literature of the last 20 years.

So the first chapter is a slapdash historiographical summary written not to inform the reader, but to push the author's views as a traditionalist Catholic. The historiography of the last 20 years is passed over in a few sentences, which is very poor in a historiographical summary.

I also want to highlight a passage from the conclusion of the book because it has a similar point, but the mask of historiographical discussion is off:

"The Crusades were an inherently Catholic undertaking. They were promoted by the papacy, encouraged by the clergy, and fought by Catholic warriors. An authentic understanding of the Crusades, rooted in a contemporary perspective, is best achieved by those who believe today what the Crusaders believed. Catholics are uniquely positioned to understand the glory of the Crusades, and to help those outside the Church begin to see it."

This is not how the study of history works. You do not have to be X to write a good history of X. It can help, but it can also hinder. Here it definitely hinders.

The Second Chapter Lies by Omission

The second chapter, on the origins of the idea of crusading, is better. Much of it just regurgitating generally accepted scholarship on the early development of Christian holy war drawn from the scholars he skipped in the introduction, so it's hard to go wrong. But there are notable places where he does. For example, there is this curious passage on the idea of crusades as wars of conversion:

"A final brief clarification is in order. Despite the belief of modern-day critics, the Crusades were not wars of conversion comparable to those that had helped Islam spread by the sword. Indeed, engaging in warfare simply for the conversion of others was never a criterion for just war, nor does the historical record indicate that this is what motivated the Crusaders. For the individual Muslim, conversion to Christianity was (and still is) rare and dangerous; any such conversions were only a subsidiary benefit to the Crusaders, who saw their expeditions primarily as defensive, just, holy wars designed to reclaim Christian territory from the hands of aggressive and harassing Muslims. “The Crusaders weren’t fighting in the East to save the souls of unbelievers or to extend the bounds of the Christian religion. They fought to win salvation for themselves and to recover or defend sites that were sacred to their faith.”"

The quote at the end there is from a history of the crusades called Fighting for the Cross, which is targeted at undergraduates. It's fine, but it really shouldn't be used as an authoritative piece of scholarship by people above that level of education. The idea that crusaders did not fight to forcibly convert their enemies is a dodgy one, and to be honest I'm surprised that Fighting for the Cross presents that view because there is plentiful evidence to the contrary. The First Crusade forcibly converted some Jews and Muslims, the lead preacher of the Second Crusade (Bernard of Clairvaux) wrote about the mission of crusade as one of conversion or extermination, and some crusades were accompanied by preaching missions. Entire books have been written just on conversion as a mission of crusaders. The Glory of the Crusades is absolutely misrepresenting history here, and to do so it quotes an introductory book for first year undergraduates, because anything less simplified would expose the complexity of the issue.

Another notable omission, and again one I think is deliberate, is vengeance as a motive. The author's main objective is, as is clear from the title, to glorify the crusaders. To do this, he has to avoid giving the impression that many crusaders loved violence; that they were angry brutes who got a kick out of killing Muslims. However, the inconvenient truth is that a lot of them were. There were people like Thomas of Marle, portrayed in crusade texts (except Guibert of Nogent) as a hero of the First Crusade because he was one of the first over the walls of Jerusalem in 1099, but is described by people who knew him (especially Guibert of Nogent) as the most evil and sadistic man they had ever met. As with conversion as a motive, entire books have been written about vengeance and anger as motives for crusaders, but The Glory of the Crusades does not inform the reader of any of that. The result is that the reader is misled.

As with the introductory chapter, this one is not actually written to inform the reader but to push a traditionalist Catholic agenda. It oversimplifies the complex motives of crusaders, omits important scholarship on crusading motivations, and only discusses the motives that make crusaders look good by current moral standards.