This is a very recent acquisition and I've already identified some feathers I've had for ages and some I just found. Yikes! Did I cop to a felony just now? I sure did. It's illegal to possess feathers from birds here in the US unless they came to you by way of legal hunting (like ducks etc.). Just picking them up and taking them home is a no-no even if they were naturally molted or because the bird died. Somehow I don't think the feds are going to come and break down my door. Seriously, I learned a ton just from the introductory text about flight mechanics and specifically how birds are built to do it perfectly; from their feathers to the way their lungs work (hint; not like mammalian lungs). It's organized by bird type (wrens, woodpeckers and allies, herons, bitterns and allies etc.) and shows the primary and secondary feathers lined up as they would attach to the wing. It also shows tail and contour feathers for most birds with representative measurements. Altogether a terrific book. ( )