Just in time to make your Christmas shopping list is R. Crumb’s “The Book of Genesis,” now on display at the Hammer Museum. Display is really the wrong word; It’s more of an interactive exhibition. Every page, all 200 of them, is framed and hung and yes, people really do start “in the beginning” and read their way along the wall to the end. Why, you might ask, wouldn’t you just buy the book and read it sitting down? What’s presented at the museum are Crumb’s original drawings, including all his corrections and whiteout marks. The pages “become incredibly alive when you see the hand of the artist in the work,” says Crumb’s gallerist, Paul Morris. In fact, while Crumb was perusing the exhibit, he noticed one last mistake and took the page out of its frame to fix it.