Well, first I have to say that this image achieves the primary goal of a book cover: it caught my interest and made me want to take a closer look. The wand, feather, and spine of the book all point towards the main title and help draw focus to it, though I feel that the sub-title is getting a little lost, with both the plainer font and the smaller size. When I first looked at it, I was trying to process it as a second author name, since it matched the actual author line so closely. I do like the faded area behind the sub-title though; that's what kicked my brain back into actual comprehension.

I also really like the rendering and design of the book, it looks at once hefty, arcane, and decidedly interesting.