This comprehensive survey addresses the key issues and questions that arise under German data protection law. An essential reference work, it explores the fundamental principles of both German and European data protection law. It examines the role of the supervisory authorities, specifically those tasks of the Data Protection Supervisor. It gives crucial direction on how customer data can be handled for advertising purposes. It sets out the obligations of companies and corporations with regard to employee privacy. It also looks at the data transfer inside and outside the EU. A seminal text: it will be required reading for all practitioners in the field of data protection both within Germany and the wider European Union.