This chapter provides a broad introduction to this Handbook on small satellites. It offers information as to why this Handbook was created and its primary uses. It provides guidance as to the structure of the Handbook and its Appendices and a useful information as to how the text of this Handbook and its references can be employed to understand about the history, the technology of small satellites, ground stations and systems for users of these small satellites, the operation of these facilities, launch services, as well as definitions concerning the many different types of these small satellites that exist today. It also provides information, explanations, and definitions about the economic, legal, policy, and regulatory aspects of these systems. It has an entire section devoted to providing information about the many diverse and growing aspects of applications and services that can be used by employing small satellites and how they are uniquely able to provide some of the newer and more entrepreneurial space-based services. There is a chapter that relates the uses of small satellites as a means to achieve the United Nations Sustainable Development Goals (SDGs) for 2030. In short this Handbook seeks to provide a comprehensive set of information about all aspects of smallsats, their uses and applications, the related ground systems, their launch and operation, as well as related economic, legal, policy, business, and financial aspects of these new types of space systems. Finally it seeks to address key issues and challenges for the future that include frequency allocation and management, orbital space debris, space traffic control and management, as well as competitive technological, business, economic, and financial issues. It also notes that the COVID-19 pandemic will have a major impact on the world economy and that this will include a major impact on the small satellite and launch industries. In short there will likely be a number of bankruptcies in this field as a direct or indirect consequence, but these setbacks do not impact the innovative technologies or other information presented in this handbook.