The 13 Clocks: Grimm's Fairytales meet The Phantom Tollbooth

I discovered The 13 Clocks by reading Neil Gaiman's introduction to the 2008 New York Review of Books edition (which I found in The View from the Cheap Seats, a massive collection of Gaiman's nonfiction), where he calls it "Probably the best book in the world" -- how could I resist?