We have known since the Theros worldbuilding panel at PAX Prime this year that the Theros block e-book series is to be authored by longtime Magic Creative Department writer Jenna Helland. Beyond some minor plot details (Elspeth being a reluctant protagonist and Daxos somehow being dragged along on her path), however, we really have no idea of anything else about the books - until now.
Amazon.com has, in its Kindle section, a preorder page for "Theros: Godsend, Part 1," apparently due out in April 2014 (but, realistically, since Journey into Nyx will be the focus of everyone's attention by then, sooner than that). The price, just as with the Return to Ravnica block e-books, is $1.99, a relative bargain offset by the low overhead of publishing as online-only.
The "Part 1" of the title means the overarching plot is to be serialized in three set novels, just as The Secretist was.
There is, sadly, no book cover for us to admire yet, but with this low-profile announcement, more details are surely to come soon, and Jenna Helland herself will likely promote it when she next writes an Uncharted Realms article on magicthegathering.com.
Interested in the lore of Theros? Thinking of picking up a copy of Godsend? Let me know in the comments.