xxvi Acknowledgements For the extensive updating for this fourth edition I have needed to consult a large number of resources and I have been greatly helped in this by the Library staff at Northumbria University and at Newcastle University And finally my thanks are due to Chris Waterston formerly of Newcastle University specifically for his contribution to the two mind maps in Chapter 7 but also for his constant support and patience during the many stages of writing the various editions of this book xxvi Acknowledgements For the extensive updating for this fourth edition I have needed to consult a large number of resources and I have been greatly helped in this by the Library staff at Northumbria University and at Newcastle University And finally my thanks are due to Chris Waterston formerly of Newcastle ...University specifically for his contribution to the two mind maps in Chapter 7 but also for his constant support and patience during the many stages of writing the various editions of this book