The first German book on the ISTQB Certified Tester - Advanced Level Specialist - Security Tester. The teaching material has been expanded with additional information and practical examples. It is suitable as a textbook, supplementary literature for relevant training, and for self-study. The authors provide a solid introduction and a practice-oriented overview of the technical, organizational, and procedural aspects of security testing, imparting the necessary practical knowledge to ensure the required security for modern IT applications, which is essential for the economically viable and regulation-compliant deployment of software systems. The book covers in detail: fundamentals of security testing, purposes, goals, and strategies of security tests, security testing processes, and security tests throughout the entire software lifecycle.