He was cold. He was cruel. A ruthless sensualist riding headlong to hell. He was the Silver Devil – Domenico, Duke of Cabria.
Felicia was the illegitimate sister of a tavern-keeper. She felt nothing but terror when they told her she had been chosen as the Duke’s next mistress, and when they took her, decked in silks and jewels to the Silver Devil’s bed… (from the back cover 1978 Troubadour edition)

The Silver Devil is an extremely unique romance novel set in Renaissance Italy, with an compelling and memorable cast of characters. While it doesn’t twist the archetype of ‘rich man, poor mistress’, it does delve into the darkest, blackest depths of where such a story could possibly go.
As the reader, I never came to like any of the characters. Far from it. The hero was a psychopath, the heroine was mostly wallpaper, and the majority of the secondary characters were truly abhorrent. Many scenes in this book were horrific and shocking to the extreme. However, while the characters are dislikeable, they are also undeniably fascinating and vividly drawn, and the Renaissance Italy setting grabs you by the throat and doesn’t let go throughout the whole book.
I would rate this 4 out of 5 stars, and recommend it with reservations. I have never come across another book quite like The Silver Devil, and I don’t believe I will again. Despite melodramatic plotlines, shock value and truly abhorrent characters, the novel is well written and extremely well done.
I have a long (almost 5000 words) comprehensive and spoiler heavy review here, in my journal, but for those who don't want spoilers, here is The Silver Devil on goodreads, a thread on All About Romance, and two other reviews I have come across here and here.