Natural Language Processing and Information Retrieval is a textbook designed to meet the requirements of engineering students pursuing undergraduate and postgraduate programs in computer science and information technology. The book attempts to bridge the gap between theory and practice and would also serve as a useful reference for professionals and researchers working on language-related projects. Integrating two rapidly developing and popular research fields of language processing and information retrieval, the book provides an extensive coverage of various concepts and widely used techniques in these areas. The text includes topics such as language modeling, lexical analysis, computational modeling, grammar and parsing, and semantic as well as knowledge-based analysis. The statistical and semantic approaches are explained with examples from Hindi, English, and Urdu. Besides presenting traditional applications of machine translation and natural language generation, the book discusses recent trends and practices of information retrieval, text summarization, and information extraction in sufficient detail. Written in easy-to-understand and student-friendly style, the textbook also provides ample practical applications based on hands-on research experience wherever appropriate.