Jonathan G. Nelson replied to the topic Rise of the Drow – Darkness Arrives (possible spoilers, I guess?) in the forum Adventureaweek.com 5 months, 2 weeks ago
RISE OF THE DROW in hardcover sold out long ago, it was a limited print run with only 650 copies in existence. It will never be printed again in that format.
You can, however, find the softcover version on DriveThruRPG.com here:
This is by far our most popular series. Hopefully, you picked up the Kickstarter version and if you didn’t, please check out http://drow5e.com/