New York (CNN Business) A version of this article first appeared in the Reliable Sources newsletter. You can sign up for free right here.

Trump's $$$$

Susanne Craig says this investigation was, without a doubt, the hardest story she's ever done.

"Imagine," she says, "someone tossing a million white puzzle pieces into Times Square and being asked to put it back together."

Those puzzle pieces were about the Trump family business. Craig, David Barstow and Russ Buettner pieced it all together for an extraordinary story , published by the NYT on Tuesday afternoon. It will fill eight special pages of the print edition on Wednesday. Here's the front page:

Now for the story behind the story...

NYT assistant managing editor Sam Dolnick called this "investigative reporter serendipity:" Exactly two years ago, on October 1, 2016, "the same NYT crew published a Trump taxes story after an anonymous source sent Susanne Craig 1995 tax records," he tweeted.

Trump, of course, was elected without ever disclosing his taxes.

Flash forward five months. In March 2017, David Cay Johnston obtained a copy of Trump's 2005 returns. (Remember when he broke the story on Rachel Maddow's show?) "That triggered our journey," Craig told me. So it's fair to say this was an 18-month investigation...

The sourcing

The trio obtained confidential tax returns. Financial records. Depositions. And so on. How? I'll leave that up to you to speculate.

"We had thousands of documents. Hundreds of tax returns," Craig told me. "Piecing all that together, understanding what they did, was beyond hard. We triangulated documents. Compared tax returns to financial statements and bank statements. And then talked to sources on it. Today we put it into one story, all explained. But it started with piles" of information sitting in the corner of the room.

A room with a locked door

Buettner, Barstow and Craig worked in a small room on the fourth floor of NYT HQ. One of the only treats: a bottle of Jameson on the shelf.

Most NYT reporters work from open cubicles. But the trio needed privacy. So the room was kept locked, and they were the only ones with keys...

A multimedia rollout

I mentioned the "takeaways" list earlier. The NYT also had a video ready to go on Tuesday. And the same documentary crew that made "The Fourth Estate" for Showtime also tagged along on this investigation. Showtime will air the resulting "documentary short," titled "The Family Business: Trump and Taxes," this Sunday at 8:30 p.m. ET. It's directed by Jenny Carchman, produced by Liz Garbus and Justin Wilkes... And it's still in the works... It'll run approximately 30 minutes on Sunday...

Trumpworld's threat: Harder calls the story "highly defamatory"

When the story dropped on Tuesday, many journalists commented -- in awe and envy -- on the super-confident tone of the story. The NYT reached what NPR's David Folkenflik likes to call "earned conclusions." These are not opinions -- these are conclusions that come from months and months of obsessive hard work. For example, the lead of the story: Trump "participated in dubious tax schemes during the 1990s" that included "instances of outright fraud." That is quite a conclusion.

One of Trump's pitbull lawyers, Charles Harder, sent a statement to the NYT on Monday after the paper sent him a "detailed description of its findings."

Harder said "The New York Times's allegations of fraud and tax evasion are 100 percent false, and highly defamatory. There was no fraud or tax evasion by anyone. The facts upon which The Times bases its false allegations are extremely inaccurate."

A statement from Sanders... or from Trump?

Harder's statement was followed by a release from Sarah Sanders. W.H. reporters pointed out that it sounded like it came straight from Trump's mouth.

"But the statement doesn't dispute any facts in the story," the NYT's Peter Baker tweeted. "Instead it attacks the newspaper and repeats the lie that the NYT apologized for 2016 coverage, which it did not."

Fox's spin

Here's the thing about an 18-month investigation like this: There's no real way for other news outlets to "match" the story for days... or more realistically for weeks or months. So other outlets have to report it with attribution to the NYT. I found it funny when Fox's Kevin Corke told viewers, during the 4 p.m. hour, "we'll keep digging." How? Well, he said he had reached out to W.H. officials. I can't think of a worse possible way to report on Trump's taxes.

Anchor Neil Cavuto, meanwhile, downplayed the story by saying "I don't know if there's a there there." This is one of those times when Fox's coverage actually does a disservice to its viewers...

There's still so much we don't know

This story is about the Trump family, with documents dating back decades. But what about Trump's more recent tax returns? His more recent accounting practices? "The records reviewed by the Times did not include Trump's personal tax returns or his recent business dealings," CNN's story notes.

Craig tweeted, "It really underscores the need for presidents -- Donald Trump in particular -- to release their tax returns."

Baker tweeted a similar point: "Trump could help clarify anything he thinks is misleading by releasing his tax returns, as every other president has done for decades."

-- MORE TO COME? Craig told me, "We have a lot more we want to dig into..."

-- TUNE IN: Craig is booked on "GMA" and Barstow is booked on "New Day" Wednesday morning...

The day's other Times-related news...

Oliver Darcy emails: Earlier on Tuesday, before the Trump wealth story came out, the NYT tried to put out a fire about its Monday night story involving Brett Kavanaugh and a 1985 bar fight. The Times said it made a mistake by allowing an NYT Mag staff writer who had tweeted negatively about Kavanaugh, Emily Bazelon, to co-byline the story.