Distributed systems are a collection of independent computers that appear to users as a single coherent system. They work together to achieve a common goal, sharing resources and processing tasks across multiple machines. This architecture enhances reliability, scalability, and performance, making it ideal for applications like cloud computing and big data processing. In a distributed system, components communicate and coordinate their actions by passing messages. This setup allows for fault tolerance, as the failure of one component does not necessarily disrupt the entire system. Examples include peer-to-peer networks and microservices, which leverage distributed principles to improve efficiency and resilience.