timer, canning jars and lids (2 piece lids are good) and a pot with lid deep enough to hold the jars... they sell specialized pots with lids that clamp down... never having used one I don't know the advantages. See this website for lots of info on home canning: http://www.homecanning.com/

I use American Eagle. Has a built in pressure gauge on top, and twist down giant bolt things that go through the top and bottom piece. Made in USA, they are Aluminum, made at their foundry, to our safety standards. No explosions and holes in the roof like in our parents' days. My MIL still won't use a pressure canner because of that. The clamp on ones do not seem as heavy to me, however I saw them at Walmart for a little less. But you can use them for a lot more than canning. You only need about a half inch of water, the steam builds up the pressure, making things cook faster- you could say, more intense! A rack that sits in the bottom may or may not come with the cooker, but it's good to get one with handles- makes it easier to insert and remove hot glass jars. A pressure cooker is needed for fish or meats. a regular big canning pot [looks like a giant stock pot] is all that's needed for jellies and jams, and fruit. Wide mouth jars cost more but for most things, worth the time & trouble saving... Also a big pair of square looking tong kind of things used to remove the hot jars from the water [water bath for fruits and veggies, steam for meats and fish. A plastic "jam Funnel" for jellies and jams- aids in pouring into the jars. And yes, timer, lids; rings [screw on rims] and seals [flat part with rubber gasgets], and for jams, thermometer.