In the 1880s, two extraordinary Edinburgh architects began to survey and sketch the castles of Scotland, travelling the length and breadth of the country by bicycle, on foot and by train. Together they produced an unrivalled account of Scotland’s castles, large and small. Launching her new book, Janet Brennan-Inglis talks about David MacGibbon and Thomas Ross, and how their mission contributed to Scotland’s understanding of its history and heritage, also asking what the future holds for the castles of Scotland in the 21st century.