(CNN) -- WikiLeaks is at it again.

The site will soon publish 400,000 secret documents that are expected to give a never-before-seen, uncensored view of the Iraq War. A source close to WikiLeaks said the material covers the period from 2004 through 2009 -- nearly the entirety of the conflict, which began in 2003. On August 31, President Obama declared the combat mission in Iraq over.

The number of documents in this anticipated leak could dwarf the Afghan War Diary which WikiLeaks published in July. The massive, searchable database containing more than 70,000 classified documents about the Afghanistan War is regarded as the biggest intelligence leak in U.S. history and garnered international headlines.

The ground-level view of the war was a much bleaker portrait than the official one from Washington.

This impending leak could be just as revealing.

The Pentagon, which was surprised and furious about the Afghan document leak, says it's prepared this time. It's assembled a team of 120 experts who are poised to immediately begin reading any documents on the WikiLeaks site, said spokesman Col. Dave Lapan.

"We don't know how these documents might be released, when these documents might be released, in what number they might be released. So we're sort of preparing for all eventualities," he said.

It's not just the Pentagon that's prepared. A number of media reports have focused on the release for days. Julian Assange, WikiLeaks' enigmatic director, lambasted Wired magazine and personally attacked its reporter on Twitter after a story speculating about the timing of the anticipated leak, with Assange insisting WikiLeaks does not reveal the timing in advance.

A leak, another look at WikiLeaks

This background drama -- involving Assange, those who report on his organization and those who want it stopped -- will surely mean one thing: Whatever spotlight is turned on the contents of this latest leak will be cast with equal brightness on WikiLeaks itself.

Since the publication of the Afghan War Diary, internal strife has wracked WikiLeaks. Some in the mostly secretive group of volunteers -- computer security specialists, journalists, aid workers, many with day jobs -- have quit, citing disagreements with the way the group conducts business.

Money has also been an issue. Last week, a British company that had been collecting donations for WikiLeaks ended its relationship with the organization.

Examining leaks is "a very expensive process," Assange said in August.

Daniel Domscheit-Berg, a long-time volunteer and spokesman for WikiLeaks, quit last month. He told CNN that Assange's personality was distracting from the group's original mission: to publish small leaks, not just huge, splashy ones like the Afghan War Diary.

WiiLeaks' new spokesman Kristinn Hrafnsson said the material WikiLeaks publishes is far more important than the organization or Assange, and it has tried to convey that. "In the history of Wikileaks, nobody has claimed that the material being put out is not authentic," he said.

When he left WikiLeaks, Domscheit-Berg said the site was flooded with new submissions from several countries that have not been published.

"There is now more information than can be handled," he said.

In the past few weeks, a large number of new volunteers have joined WikiLeaks to replace volunteers who have left, he said. WikiLeaks may be down, he said, but it's far from out.

Who is Julian Assange?

Then there's Assange the man, a subject of much scrutiny.

An Australian, Assange said he grew up with parents in the theater business who were on the run from a cult. Growing up, he was a computer programmer, hacker and skilled mathematician. Today, he describes himself as a journalist and activist.

He is constantly changing locations and has said he feels like a target for those who view him as an enemy for leaking secret information. Assange sometimes forgets to eat, and sleeps little. Volunteers at WikiLeaks reportedly mother him; the New Yorker witnessed one of them cutting his hair.

Shortly after the Afghan War Diary leak, prosecutors in Sweden announced that they are investigating him in two separate cases of rape and molestation.

"There is reason to believe that a crime has been committed," Marianne Ny, Sweden's director of public prosecutions, said in a statement last month. "Considering information available at present, my judgment is that the classification of the crime is rape."

She said more investigation is necessary before she can make a final decision.

Assange has maintained he's innocent and told the Arabic-language television network Al-Jazeera the accusations were a "smear campaign."

This week, his application for residency in Sweden was rejected because it failed to fulfill all the requirements. A Swedish immigration official declined to elaborate.

Assange is mercurial in interviews, and his careful, soft-spoken baritone is given to philosophical tangents on a range of topics: politics, travel, literature. Appearing to take criticism personally, he goads critics of WikiLeaks through taunting tweets.

Responding to U.S. Defense Secretary Robert Gates, who said he was "appalled" by the release of the Afghan War Diary, Assange retorted in a CNN interview that Gates had overseen "the killing of thousands of children and adults" in Iraq and Afghanistan, and criticized Gates personally for not announcing a criminal investigation based on the leaked documents.

"We will not be suppressed," Assange said.

Assange defended WikiLeaks in a September 30 interview, saying he said the group has suffered expected "growing pains."

He talks about WikiLeaks' structure but only in vague terms.

"We have increasing numbers of people, a larger budget, a formation of new supervisory structures," he said. "But all that was in the process, being researched and planned."

It is "proud in some areas [of] not being transparent," he said. "We make no apologies for not being transparent in relation to how we protect our sources, who our sources are, the structures that we use to defend ourselves from attack by significant and dangerous organizations. That is what is required. And discretion and confidentiality is important for our work. All our staff are required to understand that."

What Afghan leak revealed

The fiercest criticism after the Afghan War Diary's release was that WikiLeaks did not redact the names of Afghan informants before release, leaving them vulnerable to Taliban retaliation. Assange even said that he had not read all the documents before the site published them.

Security experts, Reporters Without Borders and at least five human rights organizations including Amnesty International lambasted the move as reckless. In the days after the Afghan War Diary leak, Joint Chiefs Chairman Adm. Mike Mullen said WikiLeaks "might already have on their hands the blood of some young soldier or that of an Afghan family."

Watch Mullen discuss WikiLeaks

WikiLeaks has said since this summer that it has 15,000 documents pertaining to the Afghanistan War that it did not release with the Afghan War Diary because it was working on redacting sensitive information.

But even without those documents, the diary showed plenty. It revealed infighting among Afghan security forces, including attacks on one another, as well as heavy drug use among Afghan soldiers. The leak also implicated Pakistan in providing aid to the Afghan Taliban (claims that Pakistan has strongly denied), and gave fleeting glimpses into Osama bin Laden's whereabouts.

It told smaller but no less revealing stories about civilians killed by "friendly action." One U.S. military report detailing the killings of six Afghans, including a child, suggested the information should stay under wraps lest it "create negative media."

How much risk?

Last weekend, CNN obtained an August 16 letter in which Defense Secretary Gates assured Senate Armed Services Committee chairman Sen. Carl Levin, D-Michigan, that the Afghan War Diary's release did not compromise "sensitive intelligence sources and or methods."

"We are working closely with our allies to determine what risks our mission partners may face as a result of the disclosure," Gates wrote.

Over the summer, the Pentagon created a team of more than 100 personnel, mostly intelligence analysts from various branches of the Defense Department, in addition to the FBI, to conduct a round-the-clock review of the Afghan War Diary documents.

Also, in reaction to the Afghan War Diary leak, Gates told reporters that the military may begin reviewing what information is accessible to troops and how they access it.

A soldier suspected

U.S. Pvt. Bradley Manning is suspected of being involved in leaking classified information. A 22-year-old intelligence analyst based outside Baghdad, Iraq, Manning allegedly confessed in an online chat room to a California hacker that he transferred data while pretending to his fellow soldiers that he was listening to Lady Gaga.

The hacker turned the instant messages over to the FBI. Manning is in solitary confinement at Quantico, the Marine Corps base in Virginia, facing eight counts of violating U.S. Criminal Code for allegedly leaking a secret military video from the Iraq War that made its way to WikiLeaks.org. Read more about Manning

Manning has not yet entered a plea, since there has not been a decision about whether he should face trial, Army Maj. Bryan Woods told CNN. Military lawyers for Manning referred CNN questions about him to Woods.

Manning has periodically been placed on suicide watch. The Army is testing the soldier's mental competency and will decide if a court martial is appropriate.

Relatives have visited Manning, the Pentagon told CNN. Among them is his aunt, a D.C. attorney who Manning lived with before he enlisted in 2007.

Supporters are helping organize donations for his defense, in case he needs a private attorney. Rallies supporting Manning across the country have also been soapboxes for people who want to speak out against the wars in Afghanistan and Iraq. A new leak will no doubt light up that debate.

A new CNN poll shows American support for the Afghanistan War has never been lower. Only 37 percent of Americans favor the war, and more than half of Americans believe the war has turned into a Vietnam-like quagmire.

CNN's Atika Shubert, Larry Shaughnessy and Adam Levine contributed to this report.