StarWars.com has the cover and official blurb for Karen Traviss’ Imperial Commando: 501st.
The Jedi have been decimated in the Great Purge, and the Republic has fallen. Now the former Republic Commandos — the galaxy’s finest special forces troops, cloned from Jango Fett — find themselves on opposing sides and in very different armor. Some have deserted and fled to Mandalore with the mercenaries, renegade clone troopers, and rogue Jedi who make up Kal Skirata’s ragtag resistance to Imperial occupation. Others — including men from Delta and Omega squads — now serve as Imperial Commandos, a black ops unit within Vader’s own 501st Legion, tasked to hunt down fugitive Jedi and clone deserters.
For a bigger look at the cover and the rest of the blurb, including some possible spoilers for Order 66, head over to the StarWars.com link above.