Most important, the documents this week could offer an infusion of new information about Donald Trump, his campaign, his White House, and its relationship with Russia. In the process, they’ll likely produce far more clarity about what his lieutenants knew, what they told Mueller, and how their differing strategies worked.

Michael Cohen

Cohen was a holdover from the Trump Organization. A Trump acolyte since 2006, he’d worked on various deals and, though he presented himself as Trump’s attorney, seemed to function more as a fixer. He emerged as an early cheerleader for Trump to jump into politics, and fulfilled some campaign duties—including having some truly baffling exchanges with reporters—though as his plea deal last week made clear, he also continued to work on a prospective deal to build a Trump building in Moscow. Cohen reportedly wanted a White House job but didn’t get one, and began to leverage his Trump connection for profit as a lawyer.

In early 2018, when the seriousness of Cohen’s legal jeopardy started to become clear, he initially took a defiant stance. Trump publicly boasted that Cohen would never flip on him (raising the question of what exactly he could flip on), and Cohen told Donny Deutsch he’d sooner jump off a building than betray Trump. He eventually came around. In August, Cohen pleaded guilty in federal court in New York to eight felony counts, including bank fraud, tax fraud, and violating campaign-finance laws—a charge on which he implicated the president in a crime.

Read: What exactly was Michael Cohen doing for Trump?

Now Cohen spoke of a different loyalty: “My wife, my daughter, and my son have my first loyalty and always will,” Cohen told ABC’s George Stephanopoulos. “I put family and country first.” (Since then, he’s taken other shots at Trump, calling for people to vote Democrat, accusing the president of using racial slurs, and more.) Curiously, he did not strike a deal to cooperate with prosecutors at the time, yet he ended up cooperating at length, including testifying for a reported 70 hours to Mueller.

It was only on November 28 that Cohen finally signed a plea deal with Mueller’s team, acknowledging that he lied to Congress about the Moscow project during testimony. The plea once again is damaging for Trump, especially because Cohen says in court filings that he told the lies while in contact with Trump’s legal team, and in order to bolster Trump’s messaging. Now Cohen has asked to be sentenced only to time served for his crimes, citing his cooperation with prosecutors in both New York and D.C. This is an unorthodox approach—cooperating without any deal, then asking for leniency after—and it remains to be seen how well it will work for Cohen. The answer might hinge on just how important his testimony is to Mueller.

Michael Flynn

Flynn seemed like the opposite of Trump: He spent a decorated career as an Army intelligence officer, with all the discipline that entails, while Trump was a flamboyant businessman who avoided military service. But the two men found common cause during the 2016 campaign, united by a fascination with Russia, hatred of Islam, and shared animosity toward Obama, who had forced Flynn out of a job leading the Defense Intelligence Agency. Flynn became a leading surrogate, lending much-needed heft to the Trump campaign and speaking at the Republican National Convention.