This chapter covers digital reconnaissance and surveillance fundamentals and prepares the reader to engage in more detailed techniques in the remaining chapters. It covers why people spy, the motivations, the risks, and the rewards. It discusses fundamental knowledge needed to mitigate the threat of stalking and what information would be relevant for security analysts and the general public. This chapter covers current events, the damage that can occur, and the many methods in which spying can be conducted. Basic cybercrime topics are also covered.