There is no book closer to my heart than a good field guide. Here is a great list of particularly helpful general ones and a few that are obsessively specific. http://blog.nature.org/science/2015/01/21/best-fieild-guides-birding-naturalist-wildlife-insects-fish-parks/
I love that Sibley and those Warblers… and I now want the fish and the squirrels!
Image copied from link.