Huzzah! According to a tweet about 10 hours ago from Bookmarks, the ongoing book festival taking place in North Carolina this weekend, Deborah Harkness announced that the third book in the All Souls Trilogy will be called The Book of Life and will be released in 2014! I haven’t able to confirm this from Ms. Harkness’s website or Facebook page yet, but she did retweet the Bookmarks13 tweet, so it appears to be factual.
Updated to add: From Ms. Harkness’s website, in August 2013:
“. . . we’re at the stage where Book #3 has enough shape that we can decide on the title. You can’t really do that until you’re sure what the book is *really* about. As soon as the publisher and I reach agreement, I promise to share it with you. Won’t it be a relief to stop calling it Book #3??”
She goes on to write that after that, they will choose a preliminary date for publication, though that may be subject to change. Apparently they have now chosen the title, though not necessarily a publication date, other than sometime next year.