Excellent, though brief, guide to this very powerful camera's many controls and functions. It goes much deeper into each of the zillion buttons, switches, and screens than the manual ever could, and the writer even discusses actual uses for each of them. Although it'd be better if many of the illustrations could be larger and in color, the clear black-and-white pictures provided are more than adequate. Good basic discussion of lenses and accessories, too, as well as information about the uses of Canon's provided software. The six-page, foldup pocket reference card is on good heavy stock and is, I think, plastic-coated and can stand up to a bit of carrying around as you get more familiar with the 1D Mark III in the field. Some of the Magic Lantern Guides I've seen aren't too much better than rehashes of the manufacturer's manual, but Michael Guncheon does a fine job of bringing the real world use of this pro camera into focus. If I were you, I'd buy it.