Also known as the Century Plant, the agave family includes over 200 species. The word agave means Noble, clearly an apt description of a plant that can live to be forty years old and grow a flower stalk up to eighteen feet tall or more. Within this large family are two plants most notable for culinary use, the Agave Americana and Agave Deserti. Both of these species are sometimes referred to as maguey.
Most agave originated in Mexico. Today the edible varieties grow in Northern Mexico, California, New Mexico, Arizona and up into southern Utah. 
The Aztecs used agave to make pulque (a weakly alcoholic version) which was used for ceremonies and banquets. Later the Spanish settlers used the fermented pulque to make mescal and tequila. Women and men over 70 years old could consume as much as they wanted on these special occasions but alcohol was otherwise very controlled for the rest of the population. It was socially acceptable to drink but not acceptable to be drunk. 
The Aztecs had other other uses for the agave as well including the making syrup, sugar, wine and vinegar. In fact, remains of roasted agave were found in caves of the Tehuacan dating back to 6500 B.C. 
The agave was an important food source of the Indians in the Southwestern U.S. According to John F. Mariani, the Apaches place agave crowns into a deep pit with with bear grass. The pit was covered over with soil and and the crowns were roasted for two days. As part of a complex ritual, the center of the crowns would be eaten and some stored for later use. The native Americans also ate the cooked agave leaves like artichokes or sometimes they boiled the leaves down to make a syrup.