Please note that the content of this book primarily consists of articles available from Wikipedia or other free sources online. Professor David Pegg is a emeritus Professor in theoretical physics at Griffith University, Australia. In his career he has made numerous contributions to NMR, quantum optics and conceptual physics including the nature of time. His h-index is at least 38. He is a Fellow of the Australian Academy of Science and a Corresponding Fellow of the Royal Society of Edinburgh. He is a recipient of the Harrie Massey Medal for Australian physics and of the Centenary Medal for his contribution to quantum theory.