The Diamond Age is actually a science fiction novel about a future world where diamonds are widely used for instead of things like money and jewelry. In this world, people use diamonds to buy and sell things and even as a form of currency. Diamonds have special properties that make them impossible to counterfeit or duplicate, so they are a great way to keep track of who owns what. In the novel, a young girl named Nell is given a magical book that teaches her all kinds of things and helps her become a leader in her community.