One of contemporary popular fiction’s best-loved characters is Jack Reacher, the former military policeman turned wandering problem-solver who’s the hero of a series of best-selling novels by Lee Child. Perhaps Reacher’s best-known maxim is, “Get your retaliation in first.”

If you know a fight is coming, in other words, don’t wait for the other guy to swing first. Take him off the table before he has the chance.

That appears to be the Vatican’s approach to two new blockbuster books containing leaked documents about the Vatican’s internal financial operations, set for release in the next few days.

Those books are “Avarice: The Papers that Reveal Wealth, Scandals and Secrets in the Church of Francis” by Italian journalist Emiliano Fittipaldi, and “Via Crucis,” by Gianluigi Nuzzi, the Italian journalist at the heart of the Vatileaks affair under Benedict XVI three years ago.

Both promise to reveal scores of previously secret Vatican documents, few of which are likely to make the Vatican look especially good.

Before either volume even appeared, the Vatican on Monday announced that two people, Spanish Monsignor Lucio Angel Vallejo Balda and Italian laywoman Francesca Chaouqui, had been detained on suspicion of having leaked confidential documents used in the new books.

Both served on a study commission created by Pope Francis in 2013, called COSEA, which laid the groundwork for his financial reform, and both would thus have had access to all kinds of confidential information.

Monday’s statement from the Vatican Press Office doesn’t lay out what the evidence is against either Vallejo or Chaouqui, although both were perceived as frozen out after COSEA was dissolved, not appointed to any position in the new financial structures, and both therefore might be considered likely candidates to leak documents.

The statement does not explicitly say that criminal charges will be filed against either, and it notes that Chaoqui is cooperating with the investigation. But it also makes clear that under the laws of the Vatican City State, releasing confidential documents is a crime.

Probably the most revealing element of Monday’s statement comes at the end, when the Vatican takes clear aim at the new books.

“With regard to the books announced for coming days, it must be clearly said that this time, as in the past, they’re the fruit of a grave betrayal of the trust shown by the Pope, and, regarding the authors, of an operation to take advantage of a gravely illicit act of turning over reserved documents,” it says.

The statement warns that the “juridical implications” of leaking documents will be taken up by Vatican prosecutors, and says that those prosecutors may request “international cooperation” — likely a reference to the fact that Vallejo is Spanish and Chaoqui Italian, and thus the Vatican would need help from authorities in those countries to make any charges stick.

Here’s the key line.

“Publications of this kind do not contribute in any way to establish clarity and truth, but rather to create confusion and partial and tendentious interpretations,” it says. “We must absolutely avoid the mistake of thinking that this is a way to help the mission of the Pope.”

In the past, journalists responsible for sensational leaks about the Vatican’s internal operations have often justified them as a service to the pope, on the grounds that the pope genuinely wants reform, but is being hampered by the people around him.

That was the way Nuzzi, for instance, presented the original Vatileaks revelations in 2012 under Pope Benedict XVI.

This time, the Vatican seems to be trying to undercut that argument before it’s even rolled out by either author.

Here are three observations about Monday’s Vatican move.

1. The Vatican has all but guaranteed these arrests will be a media sensation.

That’s achieved in part by including Chaouqui, whose original appointment to COSEA in 2013 became an embarrassment when racy photos of her with her husband made the rounds of the Internet.

She later was linked to other controversial episodes, including a VIP party on a Vatican terrace during the canonizations of Sts. John XXIII and John Paul II that reportedly irritated Francis.

Chaouqui is almost an irresistible figure for the Italian media, guaranteeing that her alleged involvement in “Vatileaks 2.0” will ramp up the buzz surrounding the affair.

2. This is clearly a new proactive strategy for the Vatican.

Rather than waiting for the bomb to go off before trying to defuse it, this time the Vatican is trying to shift the conversation before the books even come out — away from their content and toward who leaked this material and what their motives may have been.

How successful that strategy will be may depend on exactly what the books contain.

If their contents are largely a rehash of situations already broadly familiar, the Vatican may have some luck casting this as little more than sour grapes.

If, however, they provide a serious basis for questioning the seriousness or success of Francis’ financial reform, then trying to put the emphasis on where the documents came from rather than what they say probably won’t work.

3. The authors of the new books must be delighted.

The one near-certain outcome of all this is to increase interest in Fittipaldi’s and Nuzzi’s books and therefore boost sales.

All in all, it looks like an interesting few days to come on the Vatican beat.