In this chapter, we provide the basic concepts of quantum information processing, quantum information theory, and quantum error correction. The following topics from quantum information processing will be covered: state vectors, operators, density operators, measurements, dynamics of a quantum system, superposition principle, quantum parallelism, no-cloning theorem, and entanglement. The following concepts from quantum information theory will be provided: Holevo information, accessible information, Holevo bound, Shannon entropy and von Neumann entropy, Schumacher’s noiseless quantum coding theorem, and Holevo-Schumacher-Westmoreland theorem. The basic concepts of quantum error correction are introduced as well.