Due out in September, and bringing to an end the TOS trilogy Legacies, is Purgatory's Key, by Dayton Ward and Kevin Dilmore. Thew new cover features the Enterprise swooping down on the mysterious structure that was first revealed on the cover of the previous book in the series.
Here's the back cover, including the blurb:
Like the rest of the Legacies series, there will also be an audiobook release of this title, featuring an extended version of the cover art - That has yet to be revealed however.
A new adventure begins in October, with a (mostly) 24th century trilogy featuring the Klingons: John Jackson Miller's Prey. The cover for the first book in that series, Hell's Heart features both the Enterprise-E and the Enterprise-A, as well as a couple of Klingon Birds of Prey (via StarTrek.com):
The back cover for this one hasn't been released yet, but here's the blurb anyway:
When Klingon commander Kruge died in combat against James T. Kirk on the Genesis planet back in 2285, he left behind a powerful house in disarray . . . and a series of ticking time bombs. The Phantom Wing—a secret squadron of advanced birds-of-prey. A cabal of loyal officers intent on securing his heritage. And young Korgh, his thwarted would-be heir, willing to wait a Klingon lifetime to enact his vengeance.
Now, one hundred years later, while on a diplomatic mission for the United Federation of Planets, Captain Jean-Luc Picard and the crew of the U.S.S. Enterprise are snared in the aged Korgh’s trap—and thrust directly in the middle of an ancient conflict. But as Commander Worf soon learns, Korgh may be after far bigger game than anyone imagines, with the key being in a discovery made long ago by another first officer of the Enterprise—confronting the Federation-Klingon alliance with a crisis unlike any it has ever seen!
To keep track of all the latest releases, hit the books buttons on my 2016 and 2017 schedule pages. You can also find series reading lists and author bibliographies on my dedicated Star Trek lists site.