ROGER EBERT: I am but a naive outsider. I don’t fully understand the working of the “derivatives” and “credit swaps” that we have heard so much about in recent months. I’m not alone. But I’m learning. I gather that these are ingenious computer-driven trading schemes in which good money can be earned from bad debt, and Wall Street’s Masters of the Universe pocket untold millions at the same time they bankrupt their investors and their own companies. This process is explained in a shocking documentary named “Inside Job,” which was just named the best single film at Cannes 2010. It wasn’t in competition. The voters in the poll were a group of 19 movie critics polled by IndieWire. (I wasn’t one of them.) It was the only film to earn an A average. It is a very angry, very carefully argued, brutally clear documentary about how the American financial industry set out deliberately to defraud the ordinary American investor. It was directed by Charles Ferguson (below), whose academic, business and government backgrounds make him unusually well-qualified for this subject. The remorseless narration is by Matt Damon. Here is the argument of the film, in four sentences. From Roosevelt until Reagan, the American economy enjoyed 40 years of stability, prosperity and growth. Beginning with Reagan’s moves against financial regulation, that sound base has been progressively eroded. The crucial federal error (in administrations of both parties) was to allow financial institutions to trade on their own behalf. Today many large trading banks are betting against their own customers. MORE