How The Scots Invented The Modern World - Arthur Herman
The '45 - Christopher Duffy
Skinful of Scotch - Cliff Hanley
Pretty much anything else by Cliff Hanley
Scotland for Beginners - Rupert Besley
Folklore of the Scottish Highlands - Anne Ross
The Adept series - Katherine Kurtz and Deborah Harris
Caledon of the Mists - Deborah Harris (not strictly about Scotland, but really ...)