The ebook is available now, but as Preston explained in his review, Amazon is responsible delaying the release of the Kindle edition:
Just to be absolutely clear about this: the delay in the Kindle release of Blue Labyrinth was entirely due to Amazon and had nothing to do with Hachette, despite Amazon's assertion to the contrary. Whether this was an honest mistake on Amazon's part or something else is not known. The problem seems to be taken care of now, and we hope Kindle sales will go smoothly from now on.
Thank you all for your patience and for being such loyal readers, which is much appreciated!
Preston was responding to the double handful of one star reviews left by frustrated fans. That ebook was due to be released on 11 November, but for some unknown reason it was delayed until about 2 pm eastern on that day.
Ten readers took to the review section to voice their displeasure first thing Tuesday morning (out of approximately 150 reviews as of 13 November), and Preston responded today with a 5 star review which blamed Amazon.
The review has since been taken down by Amazon, but not before someone snagged a screenshot:
As you may recall, Doug Preston is the leader of Authors United, the nonpartisan authors group which formed to peacefully bring about a deal between Amazon and Hachette.
As a long time observer of publishing, I can assure you that all of Preston's statements have shared a similar balanced and nonpartisan viewpoint.