Harry Potter Characters of the Magical World book
It's the same size and format as the Star Wars Character Encylopedia and features, it says, 'every LEGO Harry Potter minifigure and creature'.
As is usual with DK books, the photography is excellent, even though I say so myself: it features several hundred images that I was commissioned to take for it :-)
Also in common with recent DK books, it comes with a unique minifig. It's Harry Potter in the outfit he wore to the 'Slug Club Christmas party', apparently. It has to be said that it's a bit boring but I think it's safe to assume that this will the last Harry Potter theme minifig ever, so it's one collectors will want to own anyway.
I'll do a longer review and post pictures of the book in due course. If you can't wait for that, you can order/preorder it from Amazon below.