This book provides a detailed account of quantum theory with a much greater emphasis on the Heisenberg equations of motion and the matrix method. No other texts have come close to discuss quantum theory in terms of depth of coverage. The book features a deeper treatment of the fundamental concepts such as the rules of constructing quantum mechanical operators and the classical-quantal correspondence; the exact and approximate methods based on the Heisenberg equations; the determinantal approach to the scattering theory and the LSZ reduction formalism where the latter method is used to obtain the transition matrix. The uncertainty relations for a number of different observables are derived and discussed. A comprehensive chapter on the quantization of systems with nonlocalized interaction is included. Exact solvable models, and approximate techniques for solution of realistic many-body problems are also considered. The book takes a unified look in the final chapter, examining the question of measurement in quantum theory, with an introduction to the Bell's inequalities.Contents:A Brief Survey of Analytical DynamicsDiscovery of Matrix MechanicsMathematical PreliminariesPostulates of Quantum TheoryEquations of Motion, Hamiltonian Operator and the Commutation RelationsSymmetries and Conservation LawsBound State Energies for One-Dimensional ProblemsExactly Solvable Potentials, Supersymmetry and Shape InvarianceThe Two-Body ProblemMethods of Integration of Heisenberg's Equations of MotionPerturbation TheoryOther Methods of ApproximationQuantization of the Classical Equations of Motion with Higher DerivativesPotential ScatteringQuantum DiffractionMotion of a Charged Particle in Electromagnetic Field and Topological Quantum Effects for Neutral ParticlesQuantum Many-Body ProblemQuantum Theory of Free Electromagnetic FieldInteraction of Radiation with MatterBell's InequalityReadership: Advanced undergraduate and graduate students in physics, chemistry and applied mathematics; researchers in nuclear and particle physics.