Greg Miller has covered national security since 9/11 — first for the Los Angeles Times, and since 2010 for The Washington Post. The past two years have been unlike any of the rest.

“It’s really bewildering,” he said. “It’s not just the story — which is the craziest and most complicated that any of us have ever seen — but the fact that while covering it, our institution, journalism, is under siege in a way that none of us has ever experienced.”

The story is Russia’s attempt to influence the 2016 presidential election in President Trump’s favor, and the continuing fallout of that effort. Since before the election, Miller, a two-time Pulitzer Prize winner, has been digging deep into the Kremlin’s efforts to help Trump emerge victorious, and then into special counsel Robert S. Mueller III’s subsequent investigation. Washington Post journalists from across the newsroom contributed to the reporting. Custom House, an imprint of HarperCollins, will publish Miller’s extensive account on Oct. 2 in “The Apprentice: Trump, Russia and the Subversion of American Democracy,” according to a press release.

As part of the team that won this year’s Pulitzer for national reporting along with the New York Times, Miller has contributed significantly to The Post’s coverage of this subject. The awarded work provides a framework and basic understanding of what happened, he said, but his book incorporates much of what was “left on the cutting room floor,” and then some. He estimates that around 80 percent of “The Apprentice” will be original reporting based on hundreds of interviews with people close to the four major players: Trump, Mueller, Russian President Vladi­mir Putin and former FBI director James B. Comey.

It is a difficult task to have taken on, given the accelerated speed at which news breaks nowadays.

“Every time something happens, we are folding new details in,” he said. “Every Mueller indictment has had new information in it that gives us a deeper understanding of the events during the election, so all of that is incorporated in real time.”

“The Apprentice” begins with Russian hackers probing the Democratic National Committee’s computer network — it includes “details upon details” on how they did so — and concludes with the Trump-Putin summit held last month in Helsinki. Miller conducted a vast number of additional interviews with senior officials in both the Obama and Trump administrations. The book draws on reporting over the past two years by the National, Foreign, Business and Local staffs and is illustrated, in part, with photos by Post staff photographers. A number of Miller’s colleagues also did additional reporting for “The Apprentice,” notably Devlin Barrett, Karen DeYoung, Elizabeth Dwoskin, Tom Hamburger, Rosalind Helderman, Sari Horwitz, Greg Jaffe, Ellen Nakashima, Julie Tate, Craig Timberg, Anton Troianovski and Matt Zapotosky.

“This book does not exist without the work of dozens of other reporters and editors,” Miller said. “In fact, there are scenes in the book that go into that, where we turn the camera back on ourselves in the newsroom and talk about some of those stories and go as far as we can, while protecting the sources, about how those came together.”

The book’s title riffs on the president’s former NBC reality show, but Miller said “it works on so many other levels.”

“He’s an apprentice in terms of his lack of preparation for this job, the extent to which he’s learning in office — or not learning, in some cases,” he continued. “His odd relationship to Putin and the way he seems so subservient at times has an apprentice-like aspect to it as well.”

“The Apprentice” follows Miller’s 2004 debut, “The Interrogators: Inside the Secret War Against al Qaeda ,” co-authored with Chris Mackey. Miller also contributed to The Post’s coverage of U.S. surveillance programs revealed by Edward Snowden, which won the 2014 Pulitzer for public service. He was a finalist in 2013 for “Permanent War,” a series of stories on the Obama administration’s counterterrorism policies.

Miller’s latest book deal came together in mid-2017, he said, at which point the national security team was writing “breaking story after breaking story.” “The Apprentice” uses a narrative approach to deliver what he called “the most complete and authoritative version of that.”

Custom House editorial director Geoff Shandler said in a release, “Greg Miller and the team at The Washington Post have been working on ‘The Apprentice’ since April 2017, and it shows — no other book has covered the investigation into Russian interference in the 2016 election with greater scope and determination to get to the truth.”