Attorney General Barr

In a letter dated March 27, Mueller told Barr that the Justice Department's summary "did not fully capture the context, nature, and substance of this Office's work and conclusions."

What is the evidence that Barr's summary was mainstream and what is the evidence ot suggest that it was radical or fraudulent? 

Mueller investigation cost

There have been many reports that the Mueller (Special Counsel) Investigation cost the taxpayers many millions of dollars. What is the best available information about its cost?

Trump and Mueller
Donald Trump expressed concern that the Mueller investigation was biased against him because there were 13 Democrats (either registered as Democratic, or donated to Democratic Party candidates) and no registered Republicans among its investigators. What are the reasons to believe that the team was biased, and what are the reasons to believe that they were not biased? 
Trump and Mueller

Donald Trump tweeted:

How accurate are these assertions?

Robert Mueller

For the years during which the Russia Investigation took place, there were concerns raised that the investigation itself was unconstitutional. Was it?

Robert Mueller
This argument map explores the best reasons to believe that the "Steele dossier" was what began "the Mueller investigation".