Chocolate derives from the seeds of Theobroma cacao, a tropical fruit tree, most of who's wild relatives are found growing in the humid lowlands of South America.
Excellent recent volumes present the history of chocolate, its origins, its importance for the Prehispanic societies in Mesoamerica, and the range of research currently being done on the archaeology, biology, genetics, and social history of cacao.
Coe, Sophie D. and Michael D. Coe
2007 The True History of Chocolate. second ed. Thames and Hudson, New York.
Grivetti, Louis E. and Howard-Yana Shapiro (editors)
2009 Chocolate: History, Culture, and Heritage. John Wiley & Sons, Hoboken, NJ.
McNeil, Cameron (editor)
2006 Chocolate in Mesoamerica: A Cultural History of Cacao. University of Florida Press, Gainesville.
We also recommend Wikipedia's entries for a quick overview and introduction:
This website is an interactive online database for gathering information about ancient cacao samples that have been discovered in archaeological sites and other contexts throughout the Americas. One of the main goals of the site is to allow you, whether you are a casual visitor or an active cacao researcher, to produce maps showing the chronological distribution of cacao data. These maps can be generated and viewed online or they can be downloaded to your own computer and viewed using Google Earth. Another of our aims is to allow you to download data from our database and/or to contribute your own data by contacting us to let us know about new samples or about samples we may have missed. We are seeking feedback and encourage contributions.
Last Update: October 18, 2014