The Chaos Space Marines are merciless and brutal warriors - accursed by man and god alike. Twisted beyond recognition by the fell powers they worship, their hatred of all they once held dear is writ large, corrupting their bodies just as it does their souls.
Inside the book you will find:
LET THE GALAXY BURN: The bitter tale of how the Chaos Space Marines came to be the bane of their loyalist brethren.
THE LOST AND THE DAMNED: A description of, and rules for, the battle-hungry force of the Chaos Space Marines, the potent weapons they use, and the special characters that lead them in the Long War against the Imperium.
SCIONS OF CHAOS: A stunning showcase of the range of Chaos Space Marines Citadel miniatures, presenting the colour schemes and iconography of the Traitor Legions and their Renegade allies.
SLAVES TO DARKNESS: A comprehensive army list that allows you to forge your Chaos Space Marines into an unstoppable force on the Warhammer 40,000 battlefield.
A creditable effort, if it feels somewhat unpolished. It fails to compete with other competitive codexes of the age. It doesn't integrate with the new 6th edition rules as well as I'd like. The basic tweaks to cult troops choices feel unimaginative, and the daemon engines are altogether overpriced.
That said, it is a step up over the previous codex, with many more viable options than before. Many tweaks make units more balanced--Daemon Princes cost more, bikers cost less, Noise Marines have multiple viable roles, etc. It's also marginally more fun to play; with so many options, you can change up your list between every game and try something new, model collection permitting.
Background-wise, the book doesn't disappoint--but it doesn't have too much new, either. As it has to serve as an entry-level CSM document, there isn't a whole lot new for veterans of the setting. Standard Horus Heresy boilerplate, a few new warband descriptions, a decent timeline, a few new illustrations and big events (the Abyssal Crusade, for instance).
Nothing spectacular, and a bit sloppy, but an improvement over the prior codex.
As far as codices are concerned, this is certainly on of the best ones written in the last few years. The subject matter hasn't changed much from the last version of the CSM codex, but the presentation has improved quite a lot. The backstories for characters and units have been updated and the general background section and timeline of events has been expanded. Obviously a must read for anyone playing a Chaos army in 40K, but players of other armies might also get interesting insight into the ways of Chaos by reading this book.
A great Codex - gives chaos some of it's old flavour and customization back. Some stuff in there that really doesn't make sense, like Mutilators and Warp Talons. It's also a shame there aren't cult terminators or even chosen in terminator armour. But otherwise the army is solid, but not overpowered, with plenty of choice. For me though, the big downside is a lack of background. Is there a lot there? Yes, but nowhere near as much as you would have found 15-20 years ago