This introduction presents an overview of the key concepts discussed in this book. The book begins with quite specific mathematical ideas as they are expressed and embedded in some traditional cultures. The study of the mathematical ideas of traditional peoples is part of a new endeavor called ethnomathematics. Mathematicians and others are usually skeptical of newly coined fields, wondering if they have any substance. Among mathematical ideas, this book considers those involving number, logic, spatial configuration, and, even more significant, the combination or organization of these into systems or structures. Some attempts to define mathematics emphasize its objects of study and others its methods; some definitions are extremely narrow and others exceptionally vague and broad. The particular ideas, the way they are expressed, the context and ideational complex of which they are a part, vary depending on the culture.