The book tracks Moore's early life and influences with never-before-seen family photographs and even reproduces his baptism certificate!
All his major works like Marvelman/Miracleman are covered in some depth as well as much of his more obscure creations in his various fields of comics, prose, performance, music and art, and beautifully laid out by the designer of the book Simon Goggin.
The book even offers glimpses of Moore's own personal working notebooks, like this incredible densely thumbnailed chapter from a chapter of From Hell.
Storyteller has been rescheduled to ship in early to mid July in both the UK and the US (Rizzoli/Universe) and can be preordered from any comic or book retailer worth their salt, instore or online right about now.
You can read a little more in my interview on smoky man's blog Alan Moore World.