This book presents a broad survey of how our ideas about the nature of reality have developed from the earliest prehistoric times to the present day. It looks in detail at how religious, philosophical and scientific views on the matter evolved and matured during the millennia before the start of the 'common era', and continued to do so until the advent of the 'modern era' in the 16th century. It examines the development of 'modern' science and philosophy, showing how the 'Newtonian world picture' was eventually overthrown by the 'Einsteinian revolution' that began at the start of the 20th century. It describes the development of modern astronomy and cosmology, shows how our knowledge of the 'microscopic' and 'subatomic' worlds have both increased enormously, and explores questions such as why the universe seems to be such a 'biofriendly' place, and why mathematics is so effective in describing many of its features. It then discusses 'new-age thinking' on reality, takes a broad look at the rise of atheism, and shows how 'information-based' pictures of reality are becoming increasingly influential. It argues that reality may well consist of two distinct levels - the 'phenomenal', 'empirical' world that we see around us, and the 'hidden level' that many people believe to lie beneath and beyond it. It ends by suggesting ways in which this idea might be further explored.