Consciousness is one of the major unsolved problems in science. How do the feelings and sensations making up conscious experience arise from the concerted actions of nerve cells and their associated synaptic and molecular processes? Can such feelings be explained by modern science, or is there an entirely different kind of explanation needed? And how can this seemingly intractable problem be approached experimentally? How do the operations of the conscious mind emerge out of the specific interactions involving billions of neurons? This multi-authored book seeks answers to these questions within a range of physically based frameworks, i.e, the underlying assumption is that consciousness can be understood using the intellectual potential of modern physics and other sciences. There are a number of theories of consciousness in existence, some of which are based on classical physics while some others require the use of quantum concepts. The latter ones have drawn a lot of criticism from the present-day scientific establishment while simultaneously claiming that classical approaches are doomed to failure. This book presents the reader with a spectrum of opinions from both sides of this on-going scientific debate, letting him/her decide which of these approaches are most likely to succeed.