Recently, concern about the fate of waste products produced by a whole range of industrial processes has combined with a growing realization that they may have potential uses and, therefore, value (Balakrishnan et al., 2011; Gupta et al., 2009). This has led to a large number of studies aimed at utilizing such wastes, which is the focus of this book. The following chapters discuss various selected classes of large-scale waste and their current applications and potential future applications. Chapter 2 details different wastes derived from metal processing. In Chapter 3, combustion products are discussed; here, the focus is on coal combustion products given the widespread use of coal. Chapter 4 details waste electrical and electronic equipment (WEEE) and Chapter 5 discusses food waste. Before discussing each of these classes, it is important to make a number of general considerations.