Dr. Candida Moss has provided a popular-level (as distinct from scholarly-level) account of what she calls the "myth of persecution." Unfortunately, popular-level readers may be misled by the scholarly-style nuances that Dr. Moss uses to make her case. Nevertheless, there are a number of interesting features in her work.
The overall purpose of the book seems to be disabuse readers of the idea that until Constantine Christians hid in catacombs, always fearful that Roman soldiers were about to arrest them and throw them to the lions. There may have been times it was like for certain groups of Christians in certain cities (such as in Rome during the time of Nero after the great fire).
Dr. Moss points out that the vast majority of Christian martyrdom accounts from the ante-Nicene are not historically reliable. Dr. Moss points out the work by the Bollandists who, since the 16th century, have been applying historical methods to the accounts of the lives of the saints. She then takes the six accounts deemed most reliable by the Bollandists and shows how even here the accounts are not strictly historical (see my separate discussion on Polycarp).
In the process, she notes many of the tools historians use, such as looking for anachronisms and legal or other improbabilities. She observes some of these in her criticism of Eusebius, who - in her view - was trying hard to elevate the role of bishops through a variety of techniques (see my separate discussion of her comments regarding ante-nicene bishops).
Dr. Moss also points out that many of the stories of saints and martyrs are either fictions or appropriations. She points out the example of "Saint Josaphat" as relatively indisputable example (see my separate discussion on Josaphat).
Dr. Moss seems eager to address the argument that Christians are the best and/or Christianity is true, because only we Christians have martyrs. She points out that were pre-Christian martyrs (though not called "martyrs"), such as Socrates and Maccabees. She also points out a number of pagan martyrdoms, such as Achilles' giving of his life as described in Homer's Iliad. This seems to miss the argument that martyrdom does establish the sincerity of the early followers of Christ (see my separate discussion of the truth value of martyrdom).
Dr. Moss unfortunately de-emphasizes the role of Jesus and of the author of Hebrews in discussing both the certainty of Christian martyrdom to come and the unity of that martyrdom with the past (see my separate discussion of Dr. Moss' surprising omissions).
Dr. Moss is careful in how she defines "persecution" as distinct from "prosecution." Thus, for example, a law making it a capital crime to deny that Zeus reigns in Olympus would be one that might lead to prosecution of Christians, even if the author of the law had no idea what Christians are. Likewise, Dr. Moss distinguishes between hatred, prejudice, and the like, and actual attacks. Moreover, Dr. Moss distinguishes between regional persecutions of limited duration and officially sanctioned imperial actions.
While the distinctions are understandable and even, in many ways, legitimate distinction, they can lead to popular-level confusion. For example, some may come away thinking that she is saying Christians are just cry-babies who claim to be persecuted even though they are not. Rather, I think her point is intended to emphasize the need to be cautious in how we employ persecution rhetoric (see my discussion on rhetorical excess here).
Dr. Moss' book has a number of useful remedies for those with an excessively hagiographic view of church history, notwithstanding her ironic use of a little persecution rhetoric of her own (see my discussion here). Dr. Moss seems to represent a moderately liberal/modern view of the New Testament (she is a professor of New Testament at Notre Dame, in South Bend, Indiana) and her religious views are not clearly stated (she mentions attending a mass with a colleague, but nowhere explicitly states that she is a Roman Catholic). So, naturally one should use appropriate discernment in reading.
P.S. I don't intend the above to be a comprehensive review of Dr. Moss' book. There is certainly much more that could be said, though for now, I have said what I plan to say.