If you remember "The Way Things Work", your brain probably conjures up sketches of wooly mammoths with catapults and cameras. The Way We Work has the same fantastic and creative artwork that explain a concept so well. The book goes through the biology of humans, explaining the digestive system, the nervous system, etc., and even cell and molecular biology. It's hard to believe this one book covers it all, but it does, at a reasonably sophisticated level.
I bought the book intending to gift it to a precocious child, but I quickly realized it wouldn't be appropriate because the vocabulary is too much. That's a shame, really, because anybody who can get through the jargon is more likely to need more depth of information, and be able to handle more sophisticated texts. I might use it as a general or basic reference for body systems (for example, where is the pancreas?), but then I also have an illustrated anatomy text, so maybe not.