The language model forms the foundation of NLP. This chapter introduces the N-gram language model and Markov Chains, using the classic literary work The Adventures of Sherlock Holmes by Sir Arthur Conan Doyle (1859–1930) to demonstrate how the N-gram model operates as a cornerstone of NLP in text analysis, followed by the discussion of Shannon’s model, text generation techniques, and evaluation methodologies. This chapter also serves as the conceptual basis for Workshop#2 on N-gram modeling with NLTK in Chap. 12 .