Artificial intelligence is the study and creation of intelligent machines and computer programs. There are two major types: robots and expert systems. Expert systems use symbolic processing and a knowledge base of rules to solve complex problems, often mimicking human expertise. Knowledge engineers work with domain experts to build expert systems using programming languages like LISP and PROLOG. Key developments included symbolic processing, heuristic search, knowledge representation, and the creation of knowledge bases. Major funding came from DARPA in the 1960s, which helped launch the field of AI research. Modern applications include online assistants, automated journalism, and note-taking apps. Challenges remain in areas like commonsense reasoning and embodied cognition.