Ayahuasca raises questions of interest for many disciplines. The fact that the brew is made from two different psychoactive plants (each of which is needed for the other to be useful) attracts the attention of botanists as well as pharmacologists. Originally developed by indigenous peoples during the precolonial period of South America, its subsequent adoption by nonnative groups provides anthropologists as well as scholars interested in the spread of religious traditions with an excellent case study of the ways religions change as they move into new cultural contexts. Physicians and psychologists are intrigued by the profound psychoactive properties of the brew and its ability to produce similarly profound changes in peoples’ behavior and outlook on life. And because the chemical constituents of the brew are subject to local and international regulations, ayahuasca challenges legal experts and scholars interested in human rights to reevaluate the extent and limits of religious freedom and the proper role of governments in regulating religious behavior. The 27 contributions contained in The Internationalization of Ayahuasca deal with these as well as other topics. The majority of these papers are updated versions of presentations given at a conference entitled “The Globalization of the Uses of Ayahuasca: An Amazonian Psychoactive and Its Users,” which was held in Heidelberg, Germany in 2008. These have been supplemented by translations of several works that originally appeared in Spanish or Portuguese.