Natural Language Processing (NLP) is a field in AI that focuses on developing algorithms and models to accurately parse, analyze, and manipulate textual and spoken data. Core NLP tasks include tokenization, parsing, and sentiment analysis. Advanced techniques involve natural language understanding and generation. Python libraries such as NLTK, Gensim, and OpenAI's API can be used for various NLP tasks, including word frequency counting, topic modeling, sentiment analysis, and text summarization. The advent of Large Language Models (LLMs) like GPT-3 has significantly improved the capabilities of NLP, allowing users to perform sophisticated language processing tasks with a single API call.