Health information provides the foundation for all decision making in healthcare whether clinical at the bed side, or at a national government level. This information is generally collected as part of systems which support administrative or clinical workflow and practice. This chapter describes the many and varied features of systems such as electronic health records (EHRs), how they fit with health information systems and how they collectively manage information flow. Systems engineering methods and tools are described together with their use to suit the health industry. This focuses on the need for suitable system architectures and semantic interoperability. These concepts and their relevance to the health industry are explained. The relationship and requirements for appropriate data governance in these systems is also considered.