Shockingly I didn't discover Dunnett till about 10 years ago, but since them I have read both her huge series of books innumerable times and still return to them for the amazing story-telling, beautiful writing, and sheer compelling-ness of her charcters.
Francis Crawford of Lymond just has to be the ultimate literary hero: brilliant, flawed, haunted and haunting; I think he was the first written man I ever truly fell in love with and it's a relationship that hasn't palled.
But these are not 'romantic' novels in any kind of reductive Mills-and-Boon or Georgette Heyer way: they are incredibly robust, violent at times, and amazingly rewarding. As other reviewers have rightly said, DD never writes down to her readers, and if that means quoting lightly in Latin, medieval French or Arabic, then she goes right on ahead to do it, because that's the way the character would speak.
Not that these are over-intellectualised, 'novels of ideas' either - they are simply the most stunning evocation of 16th century Europe, brought to us with true charcters who walk off the pages and live their lives as they choose.
In 'Kings', Lymond returns to his home in Scotland, pursued by his bad reputation and an aura of evil. Called traitor, murderer and, potentially, fratricide, he plays out the game amongst the Scottish families closest to the throne of Mary of Guise and her young child, Mary Queen of Scots.
I don't want to give anything about the plot, because it is so intricate and every small comment fits in later, but just try it for yourself and I defy you not to be enthralled!