This book is the proceedings of the 9th International Symposium on Foundations of Quantum Mechanics in the Light of New Technology (ISQM—TOKYO'08) which aims to link the recent advances in technology with fundamental problems in quantum mechanics. It also discusses fundamental problems and issues in quantum physics and places a special emphasis on “Quantum Coherence and Decoherence”.The proceedings included a special lecture by Prof C N Yang, “Pseudopotential Method in Cold Atom Research”, and 75 refereed papers covering the wide range of quantum physics: cold atoms and molecules; spin-Hall effect and anomalous Hall effect; magnetic domain wall dynamics and spin-related phenomena; Dirac fermions in condensed matter; quantum dot systems; entanglement and quantum information processing, qubit manipulations; mechanical properties of confined geometry; precise measurements; novel properties of nano-systems; and fundamental problems in quantum physics.The book will not only serve as a good reference for experts on quantum coherence and decoherence, but also as an introduction for newcomers to this field.