This is a great compilation of all the covers for 52 (wiki) as illustrated by J.G. Jones, coloured by Alex Sinclair.
It's a hardcover book with a dust jacket. On the dust jacket is a glimpse of what's inside the book. There's a little introduction by Mark Chiarello, Editorial Art Director of DC Comics, who talks about getting J.G. Jones on board to do the covers.
In the book are the covers and the multiple concept sketches done for the them. All the covers are captioned to explain the inspiration behind. Most of the accompanying quick sketches are coloured. For every cover produced, you can see all the unused cover concepts that go behind. Oh, the art for the covers are brilliant, but you know that already.
Also included is the process of creating the 52 logo and trade dress.
There is a small section on how Alex Sinclair colours his work. It's not a tutorial but general enough to know what's going on.
If you like the comic, this book is for you.
There are more pictures of the book on my blog. Just visit my Amazon profile for the link.