Human understanding regarding the universe and nature driven forces have been thoroughly influenced by the Quantum theory as a scientific revolution. Possibly, the historical advancement of this concept mimics the history of human scientific endeavors from their birth. The book presents a valuable account of foundation, scientific history of the concept, distinct techniques to solve the Schrodinger equation, and relativistic quantum mechanics and field theory. It includes important topics such as Bohmian Trajectories and the Path Integral Paradigm, Approximate Solutions of the Dirac Equation and Theoretical Validation of the Computational Unified Field Theory. The aim of this book is to serve as an efficient reference for researchers and students.