This book deals with the coupling of two or more angular momenta, angular momentum coupling coefficients, rotation matrices, tensor operators, evaluation of matrix elements, the gradient formula, identical particles, statistical tensors and polarization phenomena, traces of angular momentum matrices, the helicity formalism and the spin states of the Dirac particle. These topics cover the entire range of angular momentum techniques that are being widely used in the study of both non-relativistic and relativistic problems in physics. At the end of each chapter, review questions, problems and solutions to selected problems are given in order to enable the reader to have a clearer understanding of the subject. Audience: This volume will serve as a valuable reference monograph for research workers in particle physics, nuclear physics and material science. It is also recommended as a text in angular momentum techniques for graduate students of physics and chemistry.