Eli Bendersky's website It seems that there are many versions of the "Arthurian" legend. This book presents one of the most common ones - King Arthur of Camelot, at the head of the Knights of the round table. The story, however, is presented from an uncommon point of view - as told by Morgaine La Fey who was, at least according to this book, Arthur's half sister.
"The mists of Avalon" tells a very complete story, from before Arthur's birth, telling about his (and Morgaine's) mother Igraine and her sister - Viviane, the lady of the lake, and until after Arthur's death. Lives of many characters are traced from childhood and until late adulthood, and generally a pretty good view is given into the lives of people in those times.
There's an interesting recurring topic in this book - religion. The author deals a lot with the penetration of Christianity into Britain, and the difficulties versus the local (mostly heathen) religions. She certainly takes a somewhat anti-christian stance, not against the religion itself but rather against its priests who use it for their own benefit. Somewhat reminiscent of today's situation with Islam. Countless times in the narrative, people from Avalon try to explain to Christians that their Goddess and the Christian god are really one God, and it doesn't really matter how one worships him / her. I found it ironic, however, that Morgaine who was a fervent preacher of religious tolerance throughout the book, ends up ruining Arthur's reign because of religious differences, although he managed to unite Britain in peace for many years. His mistake ? He did it under the banner of Christ, and not the Avalon Goddess.
There are some things I didn't like about this book. First and foremost its length. I feel there should be a justification for writing a 1000-page book, and this one doesn't really have it. The only good thing about its length is that author uses all this space well to develop several key characters in a very detailed way - Igraine, Viviane, King Arthur, Morgaine, Lancelet, Morgause, Gwenhwyfar and Mordred (Gwydion). Other than that, it just becomes "too much" towards the end.
The Arthurian conquests, great battles, matters of state are told very briefly relatively to the gossip, love affairs, and accounts of inter-personal relationships. At times the book just felt like watching a Brazilian soap opera.
The end is also quite dissapointing. I felt the last 150 pages or so are some drunken delirium, and found it hard to understand anything. The issue of the Holy Grail and the quest for it, which is quite an important part of the legent, is covered in a very unclear way - it's difficult to grasp what the story is from reading the book. Maybe I just god tired of it after 850 pages :-)
All in all, I wouldn't recommend it. If you're looking for an account of the Arthurian legend, look for something else.