This introduction presents an overview of the key concepts discussed in the subsequent chapters of this book. The book shows decreasing mineral abundance associated with the need to resort to inferior resources when deposits which are currently being worked are exhausted, confers a capitalised value on the deposits. It deals with the definition of natural resources and the nature of physical return in mining. The book discusses some of the difficulties associated with the analysis of short run return. It presents familiar aspects of return, many of the aspects have been contemptuously ignored in the recent literature of the economics of mining. The theoretical analysis of mining in the contemporary economic literature is, in many cases, thus bereft of the sort of rigorous background information which befits scientific investigation. Regardless of the reasons for the situation, it remains that the aspects are of great significance for the theoretical analysis of exhaustible resources.