Deep learning has revolutionized a number of applications in artificial intelligence, including speech, vision, natural language, game playing, healthcare, and robotics. In particular, the recent striking success of deep learning in a wide variety of Natural Language Processing (NLP) application areas has been taken as a landmark of deep learning in one of the most important tasks in Artificial Intelligence. The book presents the state-of-the-art of deep learning research, and its applications in major NLP tasks including speech recognition, lexical analysis, parsing, knowledge graph, machine translation, information retrieval, question answering, sentiment analysis, social computing, spoken language understanding, and dialogue systems. The self-contained, comprehensive chapters have been written by leading researchers in the field. It appeals undergraduate and graduate students, post-doctoral researchers, lecturers, and industrial researchers and anyone interested in deep learning and natural language processing.