I first read this book in 1995, and I'll be entirely honest, I lost track of not only time, but reality while I read. It was so engrossing, I couldn't put it down. I was completely lost in the story that Crompton wove, it was more like watching a movie in my brain than simply reading.
The story is a unique take on the story of King Arthur, and while a story from a female perspective is not new (The Mists of Avalon preceded it by just over a decade) this story, from the perspective of a member of the fey of Avalon, is different than any other I've read, and from Le Mort De Arthur, to The Once and Future King, and everything from The Sword in the Stone (based on The Once and Future King itself) to The Mists of Avalon series, I have been a fan of Arthurian myth my entire life.
So I do recommend the book. Do not take it by it's (current) cover, this is not a YA book, it does have adult themes.
The sequel, Percival's Angel was also a good book, but pales in comparison.