This chapter introduces 3D GIS (Geographical Information Systems) and explores the reasons behind this technology’s rising importance in support of archaeological documentation and spatial analysis. In addition, it provides a brief explanation of the way this instrument can be related to archaeology as a discipline. At the same time, special attention is given to the potential readership of the book, addressing a range of categories of professionals and academics who might be interested in getting to know something more about these applications. For student readers, the authors illustrate some of the possible learning outcomes that may arise from the reading of this book. This introductory chapter concludes by providing an overview of the different chapters presented and discussed in the book and clarifies how the contents introduced in the text relate to ongoing archaeological practice. The text supplies information concerning book’s structure and contents and clarifies how the text should be used.