Have you seen this book? Or "encyclopedia of books" I should say?
The Stitch Collection by Debbie O'Neill is the perfect collection consisting of five mini books. Each book is small enough (and light enough!) to be carried around in your knitting bag.
I love how it is packaged and laid out, in an organized easy to find manor. It is a set of five mini books of the stitches themselves, designed to help you choose the best stitch pattern for a particular project. Each individual stitch pattern (225 total) is ranked according to its level of difficulty and amount of drape. It basically consolidates a bunch of valuable information into a simple little book. I love that!