This book is aimed at postgraduate and Ph.D. students specializing in condensed matter physics, quantum mechanics, and the theory of relativity. It explores fundamental problems in physics that can be addressed in the mesoscopic regime. Some of the key topics covered include: a) The state of a tunneling particle under a barrier b) A local description of the state of a quantum particle c) Reality of time travel leading to reconciliation of the classical and quantum laws The book also sets the stage for developing an alternative description of quantum mechanics and how scattering phase shift can be used to probe local density of states. It highlights essential differences from traditional statistical mechanics and discusses the potential applications and future technologies stemming from breakthroughs in basic science, which will be of interest to researchers.