This is one of those stories that retells the classical story for small children. Of course, with pictures, incredible length (about four volumes) and enough new stuff to be considered a new retelling all together, not to mention a fair amount of fame, it's definitely worth reading if you want to discuss the stuff before someone starts discussing Pyle's version.  He apparently doesn't like the good girl/bad girl element in Vivian/Lady of the Lake and so divides them into two characters.  Vivian, at the direction of Morgan le Fey, seduces and kills Merlin to get his spells...then betrays Morgan.  She then works to bring down the Round Table as best she can.  The Lady of the Lake gives Arthur Excaliber, marries Pelleas, saves him from Morgan, etc.  I prefer them as one person, but they are a bunch of neat stories, if nothing else, and are a great retelling of the classical with enough changes to be interesting.

Dates:
King Arthur and the Knights of the Round Table: late 1800's