The text discusses optimizing retrieval results in a Retrieval-Augmented Generation (RAG) system by selecting an optimal reranker. A crucial component of this process is the reranker, which improves the order of documents within the retrieved set to prioritize the most relevant items. The text highlights the significance of rerankers, scenarios demanding their use, potential drawbacks, and diverse types available. It also explores how embeddings fail to adequately address retrieval challenges and introduces various reranking methods, including cross-encoders, multi-vector models, and LLM-based rerankers. The text concludes that selecting an appropriate reranker is crucial in optimizing RAG systems and ensuring dependable search outcomes by mitigating hallucinations.