Procedural content generation (PCG) refers to automatically creating game content through algorithms rather than human design. PCG aims to generate a large variety of content from a few parameters. It is not completely random, but uses techniques from AI, math, and other fields to structure the randomness. PCG offers opportunities like high content diversity, faster creation, lower costs, and adaptive gameplay, but also faces challenges like ensuring variety, aesthetics, and multiplayer compatibility. Successful PCG combines domain knowledge, AI techniques, structured randomness, and other specialized algorithms.