Thursday is D-Day. Or Mueller Day. Congress, and the rest of the U.S., will finally be able to see the Mueller Report—or the redacted version of it, anyway.

Even with the redactions, there are a number of things that we know for sure.

Special Counsel Robert Mueller and his team of 19 lawyers and 40 investigators spent 23 months on the multi-million dollar investigation. Over the course of that time, they interviewed around 500 witnesses, issued 500 search warrants and 2,800 subpoenas, resulting in dozens of indictments.

The report itself runs nearly 400 pages long, and while we do not expect to learn of additional criminal charges or anything amounting to collusion on the part of President Donald Trump, the report will, at the very least, shed light on Russia’s alleged interference in the 2016 presidential election. In January 2017, U.S. intelligence agencies concluded in a declassified report that Putin and the Russians tried to help Trump win the presidency by discrediting opponent Hillary Clinton.

Here’s what we do know about the Mueller investigation.

Who is involved in the Mueller investigation?

Many of those in Trump’s inner circle have been interviewed by Mueller’s team, including former chiefs of staff John Kelly and Reince Priebus, and ex-White House counsel Don McGahn. The investigation led to indictments of 35 people and three companies, including former national security adviser Michael Flynn, Trump’s former campaign manager Paul Manafort, the president’s longtime personal lawyer Michael Cohen, former Trump adviser Roger Stone, former foreign policy adviser George Papadopoulos, and former Trump campaign aide Rick Gates.

No obstruction of justice, according to Attorney General Barr

According to Attorney General Barr’s letter, which was sent to Congress on March 24, Mueller concluded that “the investigation did not establish that members of the Trump Campaign conspired or coordinated with the Russian government in its election interference activities.” In other words, Mueller reportedly found no evidence of collusion between Trump and the Russians—although this does not necessarily mean that collusion did not happen.

On obstruction of justice, Mueller “did not draw a conclusion—one way or the other—as to whether the examined conduct constituted obstruction.” Despite Barr proceeding to conclude in his letter that the evidence was not sufficient to determine whether Trump had obstructed justice, Mueller’s report suggests otherwise: “While this report does not conclude that the President committed a crime, it does not exonerate him.” We will likely get more information on this conclusion with the release of the report.

Trump provided written answers to Mueller’s questions

Trump provided written answers to Mueller’s team, rather than sitting for an interview. The answers his lawyers sent reportedly did not include those referring to questions related to his time as president or those concerning obstruction of justice.

Regardless of Mueller’s findings, Trump would likely not have been indicted, due to the Justice Department’s stance that a sitting president is immune from prosecution.

What we won’t see in the Mueller report

According to Barr’s March 29 letter to Congress, a number of areas will not be made public: grand jury matters, anything that could compromise intelligence, anything regarding ongoing investigations, and the privacy and reputation of third parties. We do know, however, that Mueller referred numerous investigations to other offices, including the United States Attorney’s Offices for the Southern District of New York, the Eastern District of Virginia, and the District of Columbia.

What happens after the Mueller report is released?

Barr has voluntarily agreed to appear before the House and Senate Judiciary Committees, which is he expected to do in early May. Democrats in the House and Senate will also continue their own investigations.

Oh, and if you want to get your hands on your own copy of the Mueller report, it’s already available for pre-sale on Amazon.