With this book I want to offer the reader a solid foundation for the use or study of ERP. In the book I combine theoretical aspects of ERP with a large number of practical examples and illustrations. I have only been able to do this because of the support and inspiration of a large number of people, some of whom I want to mention by name. I could never have created the theoretical basis of the book without the support of two of my Nyenrode colleagues, Prof. Dr. Ir. Jan Bots and Prof. Dr. Fred de Koning RA RE. I have acquired most of the practical experience with my ERP core team, and I want to compliment Vicky Aked, Jany Blaise, René Brouwers, Richard Cale, Henk van Deelen, Carlos Dias, Henk Haandrikman, Bianca Hendriksen, Julia Leladze, Vicky Rodgers, Pietro Trevisanato, Jan Vos, Johan Wempe and Wilmar Zwanenburg upon their perseverance and sense of humour. This English edition of the book has been peer reviewed by Klaas Brongers, president of the Dutch Computer Society Ngi-NGN; I thank him a lot for carrying out a very thorough review. Finally, I want to thank Fred Burgmans; without him I might have started writing this book, but I would never have finished it.