Preface This book is the introductory unit in a set of four books intended to provide the reader with a basic understanding of the structure, instruments, business func- tions, technology, regulation, and issues for the trading markets. Each of the addi- tional three books provides an overview of a single aspect of the trading markets. This book is an introduction for the set that will serve as a foundation for the other three books. We use the term trading markets as shorthand for trading in the financial markets. The books are focused on trading and not about financial markets as a whole. Therefore, we describe not only the act of trading but also the decisions that lead up to the execution and all the processes that follow the trade until money is exchanged for ownership, and even the accounting for positions acquired in the trad- ing process. We do not cover many important financial products and services such