So I went ahead and bought this. Haven't played it yet, of course; I have nearly a 400 game backlog at this point, maybe worse than that. The book is neat and compared with the now usual box with DVD and sheet of paper you get when you actually physically buy something, it's certainly welcome. It's obvious that a lot of care went into this. I'm not really sure why I hadn't heard of it until now, since it's been around for a few years.
I picked up Dragon Age on the recent Steam sale as well. $20 for each; I have little doubt that I'll actually end up enjoying Legerdemain more. Probably quite a bit more.