Expert systems are a type of artificial intelligence technology that are designed to mimic the decision-making abilities of a human expert in a particular field or domain. These systems use specialized knowledge bases, algorithms, and reasoning processes to provide advice, make recommendations, or solve complex problems within a specific area of expertise. Expert systems are often used in fields such as medicine, finance, engineering, and customer service to assist professionals in making informed decisions, diagnosing problems, or troubleshooting issues. These systems can be programmed to ask questions, gather data, analyze information, and provide solutions based on the rules and knowledge provided by subject matter experts. Overall, expert systems play a crucial role in automating decision-making processes, improving efficiency, and increasing accuracy in a wide range of industries and applications.