A Rule-Based System is a type of artificial intelligence that uses a set of predefined rules to make decisions or solve problems. These rules are typically expressed in the form of "if-then" statements, allowing the system to evaluate conditions and take appropriate actions based on the input it receives. This approach is commonly used in expert systems, where the goal is to mimic human decision-making in specific domains. In a rule-based system, knowledge is often represented in a knowledge base, which contains the rules and facts relevant to the problem area. The system uses an inference engine to apply these rules to the facts, drawing conclusions or making recommendations. Examples of applications include medical diagnosis systems and customer support chatbots, where quick and consistent decision-making is essential.