The document discusses the role of natural language processing (NLP) in information retrieval. It provides background on NLP, describing some of the fundamental problems in processing text like ambiguity and the contextual nature of language. It then outlines several common NLP tools and techniques used to analyze text at different levels, from part-of-speech tagging to named entity recognition and information extraction. The document concludes that NLP can help address some of the limitations of traditional document retrieval models by identifying implicit meanings and relationships within text.