A report of more than 400 pages detailing the investigation led by the special counsel, Robert S. Mueller III, revealed the scope of an ambitious Russian campaign to sabotage the 2016 presidential election and explored whether President Trump engaged in acts of obstruction to impede the investigation.

The report, which the Justice Department redacted before releasing it to the public on Thursday, cast the president in an unflattering light but did not accuse him of criminal wrongdoing. It did not exonerate him, either.

Here is what you need to know:

Lack of evidence of ‘coordination’ with Russians

The report explicitly stated that the investigation did not clear the president of obstructing justice. “If we had confidence after a thorough investigation of the facts that the president clearly did not commit obstruction of justice, we would so state,” the report said.

While Mr. Trump has tweeted that there was “no collusion,” collusion is not a legal concept.

Mr. Mueller instead was looking for evidence of a criminal conspiracy or “coordination” between the Trump campaign and Russia in its election interference activities. Mr. Mueller decided there was not enough evidence to prove coordination.