A chestnut is a tall tree producing edible nuts; it was not native to Europe, originally hailing from Asia Minor, but was spread throughout Europe by the Romans some 3000 years ago. Mount Olympus, home of the gods, was said to have an abundance of chestnut trees. Both Homer and Pliny mention them, Pliny listing all the types that are grown for food.
Indeed, chestnuts were for centuries a staple in the Mediterranean diet, and many varieties of chestnuts were cultivated throughout Europe, each selected for specific qualities for uses such as candying, roasting, boiling, drying, flour and butter (though the chestnut contains much less oil than other nuts). The poor, in particular, relied on chestnuts for a reliable source of starch.
Eastern North America too had plenty of chestnut trees, and many First Nations tribes relied on the chestnut for a food source. During colonization the wood of the chestnut, which grows straight and tall, provided timber for housing, fencing, railroad ties, and a host of other uses. It was said that chestnut trees were so numerous that a squirrel could travel all the way from Georgia to New York on chestnut trees without ever touching the ground. All that changed, though, when a viral blight was introduced from the Asian chestnut late in the nineteenth century; the American species had no immunity to it, and was virtually wiped out. Most chestnuts that grow in North America today are cultivars introduced from Europe and Asia, though attempts are being made to breed and then reintroduce blight-resistant strains of native chestnuts to the United States and Canada.
Of the many types of edible chestnut, the two most commonly seen today are the more expensive and exclusive marron, with one nut in each husk, and the cheaper and more common chataigne, with two or three per husk. (Horse chestnuts, with green spiny husks, are not edible, though the wood is used for timber.)
When choosing chestnuts, pick large heavy nuts with smooth glossy shells and no tiny holes made by insects. Chestnuts are normally boiled or roasted before being shelled; they have a hard outer shell and a bitter inner skin, both of which must be removed before the nut can be eaten.
Before boiling, make a slit in the shell, or the nut will explode. Boil ten minutes, then take out of the water and remove both layers while the nut is still hot; if the inner skin is hard to remove, return to the boiling water for a few more minutes.
For roasting, again make a slit in the shell and place in a 350°F (180°C) oven for 20 minutes, or until shells crack. Remove and wrap in a towel for 5 minutes, then peel and serve. (In some places chestnut roasters take care of all this for you from carts.)
You may find chestnuts fresh between September and February; they are also sold vacuum-packed, dried, and canned, either whole or pureed. Marron chestnuts can be candied in sugar syrup and sold as marron glacés, a popular Christmas gift. Gourmet shops also sell chestnut flour, used in some Italian pastas and desserts.
I'm sorry I can't give you any chestnut recipes; I'd be totally faking it, because I've never made anything using chestnuts.
If you feel adventurous, though, there's a very extensive list of chestnut links at
http://www.utc.edu/~jcraddoc/chestnutlinks.html#menuHere you'll find links to sites about every type of chestnut, as well as to lots of chestnut recipes.