A successful design, deployment and operation of biometric systems depends highly on the results for existing biometrical technologies and components. These existing technologies as well as new solutions need to be evaluated on their performance. However it is often forgotten that the biometric (iris, finger, face e.g.) is only one part of a fully deployed application. As biometric (sub)systems are often not designed with security and or privacy in mind, system integrators will need to address the requirements of the deployed application in this light. The fears and concerns of a significant segment of the user population need to be addressed as early as possible in the design process, to ensure that appropriate mechanisms are in place to reassure such users. These concerns may relate to privacy or to safety issues, which may be addressed in part through legal and regulatory measures. This article discusses the requirements, design and application scenario’s of biometrical systems in general and the introduction of a new biometrical passport in The Netherlands in particular. On the one hand it is based on one of the authors’ (BS) lecture notes of the Second International Summer School on "Biometrics for Secure Authentication", Alghero (IT), Summer 2005 (The summer school is co-organized by the BioSecure network of Excellence in Biometrics and supported by the European Biometrics Forum). On the other hand it is based on the other authors’ (BJ) experiences as external advisor of the Ministry of Internal Affairs in The Netherlands – which is responsible for the introduction of the new passport.