You probably already know Marek Okon, even If you don't know who is exactly him, you definetely already saw his artworks. He's one of the best digital artist nowadays, working a lot for the games industry doing concept arts for games like Crysis 2, War Hammer 40.000 and Napoleon - Total War. I've found these stunning step by step pieces on his website and though you be really cool to share with you.
If you want to know more about Marek, please acess his Website or his Devianart Profile.
War Hammer 40.000
Book Cover for "Hardcore" by Andy Remic
Napoleon - Total War
Book Cover for Fabryka Slow