Imagine a bank with branches all over the country. Each branch needs to look up accounts, process deposits, and handle withdrawals, but on your phone it just feels like one smooth banking system. Behind the scenes, the data lives on many different servers, maybe even on different continents. That’s the heart of a distributed database. In this chapter, we’ll see how these systems work, what keeps them going, and the basic trade-offs that let them run even when parts of the network break.