sons who have accomplished the individual projects. At the beginning of each chapter, we list their names and we say where the original material has been published. The original material often contains more elaborate information, e.g., about details of the modelled system and related work. I have edited the material provided by the original authors. I have modified some of the CP-nets, e.g., to improve the layout and use more mnemonic names. In some cases, I have also changed a few net components, e.g., merged two tran­ sitions or introduced a Standard ML function for operations that are used in many arc expressions. These modifications make the CP-nets more appropriate as study material, but they do not change the essential behaviour of the CPN models.