Okay, kiddo, so you remember how we talked about how people work and make things that other people want to buy? Well, in Capital Volume II, a book written by a smart man named Karl Marx, he talks about what happens after people make and sell things.
You see, when people make things and sell them, they make some money called "capital." This money is used to buy more materials to make more things to sell. But sometimes, the people who make things don't have enough money to buy all the materials they need.
That's where banks come in. Banks are like a place where people can borrow money, kind of like when you borrow a book from the library. The banks give people money to buy things they need to make more things, and then the people pay the banks back with interest later on.
However, sometimes the banks can make too many loans to too many people, and they can't pay the money back. This can cause problems in the economy, kind of like if you eat too much candy and get sick.
Capital Volume II talks about how all these different parts of the economy work together, and how sometimes things can go wrong. It's like a big puzzle, and we have to make sure all the pieces fit together just right so everything runs smoothly.