Digital evidence has become commonplace in legal practice. However, the methods of forensic computing have only partially been aligned with the requirements of the law. When do data possess high evidential value? What procedures should be followed during collection and evaluation? When is it prohibited to present unlawfully obtained evidence from IT systems in court? Dennis Heinson addresses these questions. He examines the legal conditions under which evidence from IT systems can be collected and utilized. In clear language, he explains the technical and legal backgrounds. From this, he develops requirements for IT forensics in general, and specifically in criminal proceedings and internal investigations. These provide a dogmatically sound guideline for the legally secure collection and utilization of evidence.