This chapter provides the definitions of some fundamental concepts, such as image, image technology, image engineering, image processing, image analysis, image understanding. It discusses the level structure of image engineering and some disciplines and fields related to image engineering. It also provides a survey of statistical classification of image engineering literature for the last 30 years. From which, it is seen that the development of image engineering is undergoing a fast progression, and the research and applications of image understanding techniques get more attention in recent years. One of the research directions of image understanding, the spatiotemporal technology and behavior understanding, is the topic of this book. The spatiotemporal technology can be divided into five levels: action primitive, action activity, event, behavior. Short introductions of these five levels are provided in this chapter. Each of them, according to the book structure, will be detailedly descripted and discussed by one or two chapters in this book. The spatiotemporal technology is largely supported by neural networks and deep learning, so their basic conceptions and structures are introduced in this chapter, to lay the foundation for the following chapters.