[Retrieval Augmented Generation (RAG)](https://python.langchain.com/docs/concepts/rag): LLM should read this page when developing applications that incorporate retrieval and generation, building question-answering systems with external data sources, or optimizing knowledge retrieval and integration into language models. Covers the concept of Retrieval Augmented Generation (RAG), which combines retrieval systems with language models to utilize external knowledge, access up-to-date information, leverage domain-specific expertise, reduce hallucination, and integrate knowledge cost-effectively.

