A project this size is completed only with the dedicated help of many people. Accordingly, the editors of this book gratefully acknowledge the extensive and professional work of our authors and the Morgan Kaufmann editorial team. Also, special thanks to the staff and organizers of Schloss Dagstuhl (https://www.dagstuhl.de/ueber-dagstuhl/, where computer scientists meet) who hosted the original meeting that was the genesis of this book.