This is the chronological order of events in the books. Some of the books span events that occurred in others so they overlap. The number in brackets are the order the books were published.
2000-1995 B.C.E. (approximate): Ancestors of Avalon (5)
40-61 C.E.: Ravens of Avalon (6)
81-96 C.E.: The Forest House (2)
96-118 C.E.: Lady of Avalon, Part I ("The Wisewoman") (3)
259-271 C.E.: Priestess of Avalon, Part I ("The Way to Love") (4)
271-285 C.E.: Priestess of Avalon, Part II: Chapters 8-11 ("The Way to Power") (4)
285-293 C.E.: Lady of Avalon, Part II ("The High Priestess") (3)
293-306 C.E.: Priestess of Avalon, Part II: Chapters 9-14 (4)
307-329 C.E.: Priestess of Avalon, Part III ("The Way to Wisdom") (4)
440-452 C.E.: Lady of Avalon, Part III ("Daughter of Avalon") (3)
461-539 C.E. (approximate): The Mists of Avalon (1)