This is not a book you read (well, it's certainly not a book I'd read), but it's a wonderful resource and exactly what I was hoping for, which is to find a quick way to look up unfamiliar Kanji--quicker than Jisho.org's radical look-up, which is what I've been using.
It's organized so that you first identify whether the structure of the Kanji is left->right, or top->bottom, or enclosed (by a box, or a canopy, etc.), or just it's own thing (e.g. 大). That's certainly easily done! Then it's organized by the number of strokes for the first element, and these radicals/primitives (whatever you call them) are listed on the edge of each page, so you can easily see what section you're in, and then by the number of strokes for the remaining element(s).
Even if I'm not great at counting, it's easy to check section 2-8, and then section 2-9 (aha, it's 9 strokes, silly me), and really so far I haven't spent more than 30 seconds looking anything up. I've spent as long as 10 minutes on Jisho.org before giving up before!
The entries themselves are clear and well-written—a nice touch is the necessary Kanji are printed in red, and the minor entries (e.g. rare, or only used for people's names, say) are in black, so you can feel justifiably relieved when you look one up and it's black, and a bit irked at yourself for not having learned (yet) a red one!
(5* = amazing, terrific book, one of my all-time favourites, 4* = very good book, 3* = good book, but nothing to particularly rave about, 2* = disappointing book, and 1* = awful, just awful. As a statistician I know most books are 3s, but I am biased in my selection and end up mostly with 4s, thank goodness.)