The basic problem of this book is that its entire premise is that the emperor Phillip the Arab has been unjustly neglected due to the fact that he was an Arab. If you remove that and all of the attempts to counter it then you are left with no more than a dozen pages and some nice illustrations. This accusation of prejudice ignores the rather more obvious reason for the lack of scholarly work on Phillip which is that almost nothing is known about him apart from his name. The Third Century AD is a poorly recorded century to begin with, but the reign of Phillip has probably less material than any of the other emperors of that century. The completely unreliable but thorough Historia Augusta is missing the biographies of Phillip and his immediate successor and a disturbing amount of information on the period relies on this questionable source. Without even that as a guide, deciphering his reign is near impossible. Was he a Christian for example? Some later writers thought so, but others didn't. With such little to go on the lack of scholarly works on Phillip seem to be more obviously due to a sensible avoidance of unprovable speculation rather than a deep seated prejudice against Arabs. Anyone who agrees with this will find that most of the book is taken up with wailing about the terrible persecution that Phillip and his memory have suffered due to prejudiced authors. Essentially, the majority of this book is padding.
The good thing about the book: It contains basically everything known about Philip. As I said before that isn't much, but it's nice to have it all in one place. The information about the Arabs of the Classical era is worthwhile too. I should, I suppose, comment on the irony that this work is strongly prejudiced in favor of the Arabs despite her hatred of such prejudices. Bias works both ways. More damaging to her theory of bias she mentions here that the emperor Alexander Severus was the son of an Arab, yet he was generally viewed with great favor by later writers. For what it's worth I suspect that she uses the term "Arab" in its vaguest possible sense. After the section on the Arab tribes comes a brief section on the situation in which Gordian III, emperor of Rome, found himself. Finally on page 54 Philip himself shows up for the first time in the narrative. On page 75 she makes some sweeping generalizations about Philip's Christianity and concludes that he believed in "a universalism that tolerated all religions" based on the fact that he didn't persecute Non-Christians. The simpler explanation that he simply wasn't a Christian is never considered, nor is her evidence for his Christianity explained. Similarly she states that Philip wanted to but was unable to help the poor. This also receives no attribution or evidence except for a dream she had, as recorded in her introduction. In this dream Philip appeared to her as a ghost and begged her to rescue his name from the shadows of history. Viewing this in the most charitable possible way as a narrative fiction designed to draw the reader in, it still cannot serve as evidence for his character. Pages 87-104 detail Philip's actions as emperor. There is little to state so time is taken up with more of her assumptions about his motives. The way in which she interprets the evidence is to figure out what it would have been best for him to do, assume that he intended to do it, and then find out why he didn't. Finally on page 105 we get a justification for why she considers Philip a Christian. Basically it has to explain why it showed up in some late Christian writing but never in a contemporary pagan history. The justification for this is that the Christian writers reflected Philip's private belief while the pagan historians reflected Philip's actions. Pretty weak. How these Christians were able to discern what lay in Philip's soul from across the centuries remains unexplained. just saying that "he brought back to the empire moderation and tolerance, and above all the return of constitutional government," doesn't prove it. You need a lot more than that. For those of you who speak German there is a much better and more detailed book called "Phillippus Arab, Ein Soldatenkaiser in Der Tradition DES Antoninisch-Serverischen Prinzipats" by Christian Korner.
A little background on this era: The Third Century was a terrible one for the Romans. They went through about one emperor every two years and large portions of the Empire split off from the center. Phillip ruled as Emperor for about five years near the beginning of this crisis before being killed by his successor Decius. The main sources for this era are Aurelius Victor who wrote brief accounts of all the emperors, Eusebius who wrote an ecclesiastical history (History of the Church), Zosimus who abridged a number of histories to make a brief and inaccurate one, Zonaras who wrote his history 900 years later, and the Historia Augusta (Volume 1, Volume 2, and Volume 3) which is largely fiction. All of these were written well after the fact and make little mention of Phillip. He does seem likely to have been an interesting figure, but there isn't enough known about him to write anything for certain. There certainly isn't enough information to describe Phillip as a "humane and just man, standing fast against overwhelming odds."