Arthurian Mythology

Right now I'm reading Gwenhwyfar: The White Spirit by Mercedes Lackey. I love books on Arthurian legends and this one is very hard to put down. Lackey is utilizing myths that I've only heard about in passing...for example, that King Arthur had 3 wives. It's an interesting take, told in Gwenhwfar's voice and uses more Welsh mythology & name places than I've seen used in Arthurian stories.