This book closely examines crime on the internet and the methods used by criminals through the portrayal of the phenomenon of cybercrime. It presents typical offenses (phishing, carding, DDoS, digital extortion) as well as the methods employed. After establishing a foundational understanding, it describes the known processes in the criminal underground and the structures of the perpetrators to determine whether the offenders are individual hackers or if organized structures have already formed. Building on this, the book outlines the defensive measures against attacks in this area and provides statistics to ultimately assess whether and to what extent the security of internet users in Germany is currently at risk.