If you’re looking for a resource book to add to your paper library, then Seed to Seed: Seed Saving and Growing Techniques for Vegetable Gardeners  by Suzanne Ashworth is well worth the price. With over 150 vegetables listed, Seed to Seed gives you not only the information you need to harvest the seed from your vegetables, but provides you with the planting schedules of each vegetable in the seven regional growing sections of the United States.
In this book you’ll learn what heirloom varieties are, how hybrids are gaining domination and overtaking heirloom production (and endangering that heirloom production), how to maintain the purity of your seed and crop, selecting the characteristics you want in your vegetables and propagating them, the basics of insect pollination and self-pollination, hand-pollination techniques, seed cleaning, and seed storing methods.
This book is extremely in-depth. You’ll need to take the time to read it carefully—it’s not a “get-it-in -20- minutes-and-throw-it-down” type of book. Considered the bible of heirloom seed savers, Seed to Seed will provide you all the information you need to harvest your heirloom seeds.
And when TEOTWAWKI comes, your harvested seed will not only feed your family, but will give you bartering opportunities as well. The knowledge you glean from this book may very well mean the difference between barely surviving and actually living.