Danny Greefhorst is a principal consultant and owner of ArchiXL, and works for clients in the financial and public sector. Danny acts as an IT architect and IT consultant, and is TOGAF 9 certified. He has extensive experience with the definition and implementation of enterprise architectures, application architectures and technical architectures. In addition, he coaches organizations in setting up and executing their architecture function, and is active as an instructor for several classes on architecture. Before starting ArchiXL he worked as a principal consultant at Yellowtail, as a senior IT architect at IBM Business Consulting Services and as a researcher at the Software Engineering Research Centre. Danny is active in the architecture community and regularly publishes on IT and architecture related topics. He is the chairman of the governing board of Via Nova Architectura, a portal and electronic magazine on enterprise architecture. He is also a member of the governing board of the architecture department of the Dutch Computer Science Association (Ngi).

Erik (H.A.) Proper is a senior research manager at the Public Research Centre -- Henri Tudor in Luxembourg, where he leads Services-oriented Enterprise Engineering programme. He also holds a chair in Information Systems at the Radboud University Nijmegen in the Netherlands. Erik has a mixed industrial and academic background. In the past, Erik worked for companies such as Asymetrix, InfoModeller, Origin, ID Research, Ordina and Capgemini, while interleaving this with his work at research institutions such as the Radboud University of Nijmegen, Queensland University of Technology, the Distributed Systems Technology Centre, and the University of Queensland. His general research drive is the modeling of systems. He applies this drive mainly in the fields of service science, enterprise modeling, enterprise engineering and enterprise architecting. He was co-initiator of the ArchiMate project, and currently also serves on the board of the ArchiMate forum of The Open Group. Erik is also one of the editors in chief of Springer's series on enterprise engineering.

Enterprises, from small to large, evolve continuously. As a result, their structures are transformed and extended continuously. Without some means of control, such changes are bound to lead to an overly complex, uncoordinated and heterogeneous environment that is hard to manage and hard to adapt to future changes. Enterprise architecture principles provide a means to direct transformations of enterprises. As a consequence, architecture principles should be seen as the cornerstones of any architecture. In this book, Greefhorst and Proper focus on the role of architecture principles. They provide both a theoretical and a practical perspective on architecture principles. The theoretical perspective involves a brief survey of the general concept of principle as well as an analysis of different flavors of principles. Architecture principles are regarded as a specific class of normative principles that direct the design of an enterprise, from the definition of its business to its supporting IT. The practical perspective on architecture principles is concerned with an approach to the formulation of architecture principles, as well as their actual use in organizations. To illustrate their use in practice, several real-life cases are discussed, an application of architecture principles in TOGAF is included, and a catalogue of example architecture principles is provided. With this broad coverage, the authors target students and researchers specializing in enterprise architecture or business information systems, as well as practitioners who want to understand the foundations underlying their practical daily work.