"Intended to merge key topics from both the information-theoretical and quantum-mechanical viewpoints, this graduate-level textbook provides a unified perspective of quantum information theory and lucid explanations of those basic results, so that the reader fundamentally grasps advances and remaining challenges. For example, advanced topics in quantum communication such as quantum teleportation, superdense coding, quantum state transmission (quantum error correction), and quantum encryption, especially benefit from this unified approach. Unlike earlier treatments, this book only requires knowledge of linear algebra, probability theory, and quantum mechanics." It treats the topics of quantum hypothesis testing and the discrimination of quantum states, and quantum channel coding (message transmission) with the minimal amount of mathematics needed to convey their essence. Solving the more than 330 exercises provides readers with practice that not only enriches their knowledge of quantum information theory, but also equips them with the techniques necessary for pursuing their own research in this field.