What? A spirit made from fermented grape juice, distilled just once to relatively low strengths in a continuous still.
Where? Armagnac must be made from Gascony grapes, and must be distilled and matured in this Cotes de Gascogne region, as defined in 1936 when it was granted AOC status. Just to the North of the Pyrenees and to the South of Bordeaux, Gascony can also boast to be the home of Foie Gras (the most delicious pate-based cruelty known to man).
When? Records for eaux-de-vie production in the region actually pre-date Cognac, stretching back to 1411 when a man named Antoine from Toulouse distilled a wine. Despite this headstart, the spirit has always lived in the shadow of Cognac struggling to reach worldwide markets initially through poor transport. It remains under-appreciated.
How? In a decent tulip glass, preferably without water. The lack of dilutability of the spirit has perhaps been its downfall, but if you enjoy the thwack of a cask strength single malt you should get involved with Armagnac.