The printed one.
And a bonus interactive version with the iPad download.
The interactive version was fun to play with. I spent a minute or two making that wheel drop a bunch of apples on Newton's head.
This is the kind of stuff that my kids take for granted. But, to this 43-year-old, it still feels a bit like science-fiction -- I can make the artwork come alive with my fingertip!
I thought, is this the future of illustration?
Not really, it is the present.
The cover, titled "Eureka!" is by illustrator Christoph Niemann. Where did his inspiration come from? See his step-by-step visual explanation and the cover artwork in motion here.