This graduate-level textbook on quantum theory covers important recent developments and most aspects of the theory with detailed presentations. It is also a reference and research work which provides background for research in this discipline. In addition to traditional topics, coverage includes: Wigner's Theorem of symmetry transformations, Bose-Fermi oscillators, coherent states, the non-relativistic Lamb shift, Ramsey oscillatory fields methods, the AB effect, Schrödinger's cat and quantum decoherence, quantum teleportation and cryptography, quantum dynamics of the Stern-Gerlach effect.