I'd dissent from one of the "minor criticisms" raised in another review; the illustrations are extremely clear, and far better than photos could ever be (think about it; are there any *decent* photo-based field guides for birds?). It's true that a smaller page size could allow for "pocket sized" (actually, this does fit into the big pockets of my field jacket), but that would make it harder to show confusion species on a single page (and believe me, it's easy to get confused between one potoroo and another!). The distribution maps accompanying the clear text (in the ideal, opposite-the-drawing location) are a big help here, too.