Opinion by Candida Moss, Special to CNN

(CNN)--Bill O’Reilly’s "Killing Jesus: A History" is the best-selling book in the world right now. But it’s far from flawless.

The Holy Spirit may have inspired "Killing Jesus," but he didn’t fact-check it.

Here are five ways it shows:

1. Not everything Roman historians tell you is true

Of the first 80 or so pages of "Killing Jesus," only 15 are about Jesus himself. The rest is history, biography, and politics of the ancient Mediterranean. Much of this is gleaned from Roman and Jewish historians like the imperial biographer Suetonius and the Jewish general Josephus.

These are authors that O’Reilly trusts implicitly. Maybe it’s because Suetonius reads like the National Enquirer, maybe it’s because the Romans loved eagles, but whatever the reason, O’Reilly gives them too much credit.

The Romans were fantastic record-keepers but had different standards for their history writing. O’Reilly refers to the acta diurna – a sort of proto-newspaper recording political events, marriages, and divorces that was read aloud in public – as evidence for accuracy in Roman record-keeping.

But he is wrong to see these as transparent statements of fact.

They were propagandistic: the Roman orator Cicero complains that he is misrepresented in the daily reports, and the Roman governor Pliny retells a story he had heard in which a dog jumped in the river after his deceased owner. It’s a little more Buzzfeed than Wall Street Journal.

2. Paul was not a Christian

According to O’Reilly, Paul was “a former Pharisee who became a convert to Christianity.” Paul was not a Christian; he was a Jew who moved from one branch of Judaism to another.

He never uses the word Christian. It seems that the early members of the Jesus movement referred to themselves as followers of “the Way.”

The word Christian wasn’t used until the end of the first century C.E. The first generation of Jesus' followers lived and died as Jews.

3. The Pharisees were not self-righteous bloviators.

The same old caricature of Pharisees as “arrogant,” “haughty,” and legalistic pervades the book. There is biblical support for this view from the Gospels, but O’Reilly and Dugard claim to be writing history and separating ”myth” from “fiction.”

For the past 30 years, scholarship on the Pharisees has shown that the Pharisees were not hyper-legalistic hypocrites. To make things worse, the authors seem to think that John the Baptist told the Pharisees either to burn or be condemned to hell (a rather peculiar reading of Luke 3:17).

The irony here is that our modern stereotypes of the Pharisees are grounded in Protestant critiques of Catholicism. Protestant Reformers saw Catholics as just like the biblical Pharisees, championing faith through works, and lumped the two groups together as legalizers and hypocrites. O’Reilly and Dugard, being Catholic, are actually stereotyping themselves.

4. Jesus was/wasn’t political

Any follower of Internet memes knows that Jesus can be made to say anything. O’Reilly has vacillated between saying (on his television show "The O’Reilly Factor") that Jesus was not political and arguing in his book that Jesus died to interrupt the revenue stream from the Temple and Rome and that "Jews everywhere long for the coming of a messiah ... [because] Rome will be defeated and their lives will be free of taxation and want."

Even though there’s no evidence for a direct financial link between the Temple and Rome, there’s no doubt that Jesus advocated for the poor. But O’Reilly needs to make up his mind. Is Jesus the man of the people seeking to liberate the oppressed from a heavy tax burden, or is he a peaceful man of God just trying to make a difference?

5. History isn’t just a word, it’s a discipline

O’Reilly acknowledges (correctly) that it’s difficult to look past the agendas of his sources and separate the myth from the history.

Historians prefer early sources and events that are documented in multiple (preferably independent) sources. O’Reilly puts all of this aside and cherry-picks episodes from whichever Gospel version he seems to prefer.

He will sometimes omit stories if they seem historically implausible, but he doesn’t do this consistently. He omits Jesus' words, from the Gospel of Luke, as he is being crucified: “Father, forgive them, for they know not what they do.” In his CBS interview he explained that it was impossible for people to speak audibly while they were crucified. Fair enough; but then why does he include Jesus’s final words from the Gospel of John: “It is finished”? Is there something about the word “forgiveness” that sticks in the throat?

Apart from the methodological problems, the entire book is written in the style of a novel, not a history book. We hear the thoughts of Herod as he orders the execution of the male children of Bethlehem, for instance. It’s entertaining, but it’s historical fan fiction, not history.

Editor’s Note: Candida Moss is a professor of New Testament and early Christianity at the University of Notre Dame and author of The Myth of Persecution.