It is some time after ROS and close to ANH. I have actually finished it and its a very different star wars book. No jedi and less pew pew lasers. Its actually interesting seeing the empire from the empires side.
Wow just discovered the club section! I'd like to toss out for Sci-fi the new Star Wars Thrawn Book by Timothy Zahn. Zahn is IMO the best Star Wars writer and his new series putting Thrawn back into the EU has been getting great reviews. The sequel is due out in 4 days too.
https://www.amazon.com/Thrawn-Star-Wars/dp/0345511271