Netflix's auto-rating system thought I would like this movie, and they hit the nail on the head. It's an intelligent crime thriller, with stellar acting. (Two Oscar winners, Ben Affleck and J. K. Simmons. Two other Oscar nominees, Anna Kendrick and John Lithgow. And some folks who'll be recognized someday, I'm sure.)
Mr. Affleck plays "Christian Wolff" (an alias), a high-functioning autistic, and he's in the titular occupation. His claim to fame: he helps all sorts of people (often bad people) track down financial irregularities in their (often criminal) enterprises. That's an extremely lucrative, but also extremely dangerous, calling. So far he's survived. But a brash young DOJ agent is tasked with tracking him down. Also, his newest assignment for an ostensibly honest tech firm turns out to be as dangerous as the ones he accepts from mobsters.
The main narrative is punctured with flashbacks to "Wolff's" family history and influences. This doesn't seem necessary, until it is. Stay with it, and pay attention. This movie does a better job of tying up loose ends in unexpected fashion than any I've seen recently.