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����Quantum mechanics is more than a physical theory of nature. It is a quantitative philosophy that provides us with a set of general�� overarclung principles that describe the innermost workings of our world at its most fundamental level. Due to its central importance�� all physical and philosophical theories have to be consistent with quantum mechanics. There are two aspects of quantum mechanics�� the "machinery" and the "spook." The machinery�� epitomized by the Schrodinger equation and its various methods of solution�� allows us to propagate the quantum state of a system deterministically forward in time. This aspect of quantum mechanics is not particularly "quantum��" we find it in similar form in all classical field theories. The "spook" are all those aspects of quantum mechanics that do not have a classical analogue�� not even in principle. This part of quantum mechanics is connected with the theory of measurement and its implications. Since quantum mechanics is the most basic theory of nature�� no wonder that quantum mechanics is capable of confronting basic philosophical questions head-on�� prime among them the nature of reality. ����For the longest time�� the philosophical implications of quantum mechanics were far from main-stream physics. Only very few physicists studied them because it was felt that this is idle speculation�� alien to a "hard��" quantitative science such as physics. In particular�� physicists thought that there are no consequences or applications. This point of view was fueled by the immense success of the quantum mechanical machinery�� which�� like a steam roller�� flattened and solved any "practical" problem it was applied to. In such an atmosphere of success�� questions probing the foundations of the theory appeared irrelevant and futile. ����"Shut up and calculate" was the standard response of teachers and research advisers to students of quantum mechanics raising questions concerning the meaning and interpretation of quantum mechanics.