Jasper Kent, the author of the excellent Twelve (Canada, USA, Europe) and Thirteen Years Later (Canada, USA, Europe), will publish the third volume in The Danilov Quintet this summer.
Here's a brief blurb from The Third Section:
The third instalment of the series is set during the Crimean War, when Tamara Valentinovna Komarova, an agent of The Third Section - Tsar Nicholas I's infamous secret police - discovers a new clue to a series of ancient Moscow murders. The tsar's sudden death brings the promise of new liberty for Russia, but Tamara discovers that there are those in Russia for whom freedom means only the freedom to kill.
Follow this link to read the prologue.