In preparing this study I am greatly indebted to many individuals and organisations, firstly to the Museums and Galleries of Edinburgh – the owners of the Painting – and to the Curator of Fine Art, Helen Scott, who has given much assistance and helpful advice.  The Edinburgh City Library and the National Library of Scotland have been invaluable resources and the librarians ever helpful.  I have had great help and encouragement from my family.  My daughter Alison and granddaughters Shona and Libby have read the text and suggested improvements as well as corrections. My son Nicholas introduced the idea of presenting the study as a web site rather than a book to make it more widely available and he has tried to guide his aged parent in the intricacies of modern technology.  My wife Gwyneth has given constant support and encouragement.