Beatifully done, complete with samples and fold out flaps and so forth to a very high production standard. Lovely artworks, including some by Wayne Anderson, who has to be my personal all-time favourite for spooky, icky, and just plain odd drawings. Very arch text full of turn-of-the-20th-century comments, which will probably whoosh straight over a younger reader's head. But it is hard to define what age this book is aimed at. Most of it can be read for fantasizing fun by a bright seven or eight year old, especially one who has even a passing acquaintance with the Harry Potter genre, which must be the whole planet by now, but they don't get all the jokes. They need to be a careful bright seven or eight year old too, with all these bits. And it is a wry, fun book for adults who can read it and wish their parents had got them books like this when they were young. Somewhere in the middle are older children who would appreciate all of it, but probably haven't yet grown out of claiming they've grown out of books like this. If they have, it's be brilliant for them too. Better buy it for the whole family, then.
The other thing is that there is a wealth of real stuff tucked away in the fantasy text. Darwin is in there, together with some history, a bit of runic alphabet, and some chemistry - beware if your child starts looking around for iron pyrites and flints! so you can kid yourself that it's sort of educational too.