I found a little book that I really like that just fits in your bug out bag. It is called the Nature Bound Pocket Field Guide. The book appears to be currently out of print, but is available through the used book market at reasonable prices. It has over 300 pages and measures 4 ½ x 5 inches.
This field guide has sections on fire, shelter, windchill, water, gathering food and many other things. There is a large section on edible plants with good pictures, descriptions and information on preparation and other uses. The section on poisonous plants includes pictures, symptoms and some treatment information.
This book is not going to make you into Daniel Boone overnight, but then, no book is. There are several things I like about this book. The edible plants section deals with the United States and Canada and does not attempt to cover the world. The field guide has small first aid health and hygiene sections that, while not real long, contain some good information. This may not be the right book for a very experienced woodsman, but for most of us, it will be very beneficial. It’s 4.5″ x 5″ size makes it nice and handy for any bug out bag or kit.