Regulation asks engineers to stick to privacy and data protection principles and apply them throughout the development process of their projects. However, in spite of the availability of technological solutions to identify and address different privacy threats these have not seen widespread adoption in the engineering practice, and developers still find difficulties in introducing privacy considerations in their new products and services. In this context, privacy engineering has emerged as an inter-disciplinary field that aims to bridge legal, computer science and engineering worlds, as well as concepts from other disciplines. The goal is to provide engineers with methods and tools that are closer to their mindset, and allow them to systematically address privacy concerns and introduce solutions within the workflow and environment they are accustomed to. This paper provides an introduction to Privacy Engineering, describing a conceptual metamodel useful to organize the increasing knowledge in this emergent field and make it more accessible to engineers. We exemplify some of this knowledge focusing on privacy design patterns, a set of privacy engineering elements that distill best-practices available.