Well, let's see, GeoMamma--good-quality pictures, for sure--and the kids prefer the guides where the pictures are next to the individual descriptions (in some guides, there's a big colour section in the middle, and the whole rest of the book is text, with references to the illustrations, so there's a whole lot of flipping back and forth--that doesn't work well for kids, nor for me either, actually!).

For the most part, they prefer books with drawings or paintings to those with photographs, which I think is interesting. I'm not sure why that is.

Font size and leading are important, too--it's too hard for them to read if the print is too small or the lines of type are too close together.

It's nice to have a decent binding, so the book will stay flat when it's open, without pages trying to fall out.

They prefer smallish ones, so that the books are not too heavy in their packs when we're hiking. We sort of pick what kind of excursion we're having on any given day (birds and tidepools, or trees and animal tracks, etc.), and just take two or three books with us, so that they don't get too weighed down.

mm

PS Breakaway4--how could I have forgotten cardboard? Where the rest of us see garbage, Groucho sees raw materials! Sounds like you have some of those kids, too!! It's fun, isn't it?