Expert System

Expert systems represent one of the most important eras in AI history. These systems modeled human domain expertise through rules, facts, and inference mechanisms. They had major impact in medicine, diagnosis, finance, and technical troubleshooting. Although data-driven learning systems are now far more dominant, expert systems are still highly relevant because they teach us about explainability, rule-based decision-making, and explicit knowledge representation. If you want to understand why AI is not only about data but also about structured knowledge, expert systems remain an excellent starting point.