The authors wish to thank the many people who have been involved in making this book. First, we would like to thank our editor, Lynn Townsend, who steered us and the book through its long journey from the first drafts to the book you have in front of you. Lynn's views were always helpful, creative and insightful. She was patient when the project suffered the inevitable delays that happen for a variety of reasons and always displayed great good humour. Next, we would like to offer huge thanks to Jessica Errington, our development editor, whose vision as to the ideal shape and content of the units and whose keen eye for detail enabled us to improve our early drafts of the book and to produce this final version. Nora McDonald was also a wonderful editor to work with; she applied her skills and eagle-eyes to the manuscript as it took its final shape. From there on, the production team steered the book through its demanding schedule; Linda Matthews deserves a special thank-you in that respect.
