Remember how there was a bank panic, and then there just … wasn’t? The run of failures, back in May, got stopped in its tracks by JPMorgan Chase. At the magazine, we felt glad our deposits were safe; we also felt, in an ants-contemplating-an-elephant way, like we didn’t truly understand the $4 trillion goliath that had come to our rescue. What is this thing Jamie Dimon made? How, exactly, does it make money? What will it conquer next? We asked Gary Sernovitz, a brilliant writer who drafts novels when he’s not at his private equity job, to explain the bank to us in an accessible way. His lucid, authoritative, and surprisingly funny essay is essential reading for anyone who wants to know more about the biggest of the big banks.