This was the first class that I went to at the Mother Earth News Fair last weekend, and it started the day off with a bang. Sherri Brooks Vinton shared her story of how she became interested in canning, and it was similar to mine; we both had childhoods where we visited our grandparents on their farms, and ate jar after jar of delicious homemade jam. (Her favorite was strawberry, and mine was raspberry.) I remembered thinking how strange it was (but also wonderful) to eat giant canned pears with breakfast every day. My grandparents canned everything, because at one point they'd had to; same with hers. She said that preserving food is the same as "stopping time" on it; I never thought of it that way before.
She then went into several types of food preservation; canning (boiling water, or pressure canning), fermenting, infusing, drying, and freezing. Some determining factors for what you may wish to do are: type of food, logistics (how much time/what supplies you have), utility, and taste.
Canning using the boiling water method:
You want to use this method only if you are canning acidic foods- with a 4.6 pH or less. It is a low investment (you pretty much need a big pot, some jars, a funnel, and a jar lifter-- see below).
Foods that are canned with the boiling water method are shelf-stable for a year. (This means I have some things to throw out, although I'm pretty sure my aunt still has some jam left from the 80's. The only reason I feel iffy about some things I canned is because I did them a long time ago, without an actual recipe, so I can't verify how acidic they might be.)
If you have things to can that are not acidic, or have meat or fish in them, you want to use a pressure canner. Pressure canners are pretty expensive, but they have a very specific use. You can use them to can vegetables in water, and a variety of other things. If you are new to canning, I would recommend holding off on getting a pressure canner until you want to make something that needs it. (i.e. I don't have one yet.) It can be time and experience intensive, and really, I'm just not up for that yet!
You can also pickle a wide variety of foods. I'm going to try dilly beans this summer, and I've made some fermented pickles in the past. Some foods will keep on fermenting for a very long time (like this thing called a rumtopf that sounded delicious), and some should be jarred when they are finished processing. They have a limited shelf life, but can keep in the fridge for months. If you can fermented foods, it will kill the beneficial bacteria that you've worked so hard to cultivate, so her advice was not to do it.
She also talked a bit about drying food. It's best with lower-moisture ingredients, and the results often require cooking afterwards (like sundried tomatoes). Drying takes a long time, but it's mostly unattended. You can dry herbs, fruits, veggies...and even without a dehydrator. I already dry out old bread for breadcrumbs, so this sounds pretty easy to do.
Her talk was so informative that I decided to buy her book that day. I totally recommend it, even if you have other books on canning (which I do).