Here's a great little book that would make an inexpensive yet much-appreciated gift for the gardeners and cooks on your list. (or perhaps you would like to ask Santa for own copy?)
It's "Backyard Farming's Canning & Preserving" (Hatherleigh Press, 130 pp., $5.95) by Kim Pezza. The cover states it contains "expert advice made easy" for putting up jams, jellies, sauces, pickles and more, and I would agree.
Pezza starts out with a discussion on water bath canning (for jams, jellies, high-acid fruits, juices, pickles and relishes) and pressure cooker canning (for low-acid foods including vegetables, meats and poultry).
She covers adjustments one must make to processing times, based on the altitude where you live. For example, my husband and I live at nearly 3,000 feet of altitude so must add five minutes to the time it takes to process a batch of jam in a water bath canner.
She also talks about canning jars and useful tools for processing foods safely.
At that point, the book is divided into two sections: one on hot water bath canning and the other on pressure cooker canning.
The section on water bath canning includes a wealth of recipes for making and preserving jams, jellies, preserves, fruits, pickled foods, juices, as well as sauces and salsas. What I like is that each recipe takes you through the steps to safely put up whatever it is that you're making so you don't have to flip back to the book's introductory chapter to look up those steps.
In the pressure cooker canning section, Pezza takes the reader through the process for canning vegetables, sauces, soups and stews. There are plenty of recipes for each category.
At the back of the book, there is a resource list for canning product information, a helpline and information on contacting the United States Dept. of Agriculture.
As you can tell, it's a useful book but very reasonably priced. Pezza stresses the importance of putting up your produce safely and that's truly the key to successful canning and preserving.