The Regulations for medical devices and in vitro diagnostic medical devices were published in the Official Journal of the European Union on 5 May 2017, and they entered into force 26 May 2017. A regulation is a legal act of the European Union that becomes immediately enforceable as law in all Member States simultaneously. This book gives guidance on the definitions, the key concepts and the main elements. The intention is to provide an introduction that supports the further reading of the challenging content of the Regulations.