The angle of sun is from top left to lower right. The open pages of the book are not cast in the shadow of Obama's body as it would seem they should be. They are brightly lit. His body would cast a shadow on the book held on that side of his body.
Also, it appears that the fingers on the book are casting a shadow in the opposite direction from the direction of the sun. I laid a copy of the cover over the cover shown in the photo to see if a graphic element of the cover could appear as a shadow. There are some dark images but not that would seem to match.
The cover of the book in the photo with Obama appears to be placed larger on the book than any sample of the book's cover I can find on the net (perhaps to make it easier to read the title or just a sloppy photoshop work). In fact, the word "American" in the title is actually cut off at the spine binding in the photo with Obama.
If I felt like taking the time, I could drop any book cover over the one shown. It is a pretty easy photoshop job to do.
