Ana G. Valenzuela-Zapata and Gary Paul Nabhan, Tequila: A Natural and Cultural History, (Tucson: The University of Arizona Press, 2003), 113 pages, $14.95.

Ana Valenzuela is the world's leading authority on agave plants, their cultivation and their use in making distilled Spirits. Valenzuela grew up in the heart of tequila country and she received her doctorate in biology from the Universidad Autónoma de Nuevo Leon Mexico. She has written extensively on the biology of agave as well as its traditional and contemporary cultivation. Her newest book A Indicación Geográfica Tequila: Lecciones de la Primera denominación de Origen Mexicana (2014) focuses on the use of sustainable agricultural practices in agave cultivation. Her co-author Gary Paul Nabhan is an ethnobotanist who has been studying the use of agave in the Americas for over four decades. Both Valenzuela and Nabhan were students of the late Dr. Howard Scott Gentry, a pioneer in agave botany and taxonomy.

Tequila: A Natural and Cultural History is not your typical book on tequila. Like the title suggests, the book focuses on the large number of agave varieties, some of the defining traits of the most commonly cultivated varieties and the process of cultivation for distilling tequila. Valenzuela and Nabhan also go into depth about the traditional knowledge and practices that sprung up around tequila production. One of the most interesting claims they make is that tequila is an inherently Mexican product not because of where it is made or because it uses agave, but because it is a mestizo spirit. The majority of Mexicans are mestizo, a mix of indio (indigenous) and criollo (American born Spaniards) ancestry and culture. Similarly, tequila was born from the combination of pulque (a pre-columbian fermented agave beverage) and European distillation technology. Traditional tequila production incorporated indigenous cultivation and fermentation practices learned centuries before the arrival of Europeans, with Old World technology.

The emphasis on agave taxonomy can at times seem overwhelming for those coming to the book primarily out of interest for tequila. However, this sets the stage for Valenzuela and Nebhan's discussion how the growing popularity and global demand for tequila have slowly created new methods of production agave cultivation. Large tequila distilleries buy their blue agave from campesinos (farmers) who plant and grow clones of clones of the blue agave in tight mono-cropped fields. While this is more efficient and cost effective, this practice has created a plant that lacks the genetic diversity to resists new threats from pests and disease. In 1998, forty million agave plants, or about one fifth of all agave in Jalisco were struck by a disease that rotted the agaves from the inside out. While Valenzuela and Nebhan found that blue agave fields that were inter-cropped with other varieties of agave or legumes lost fewer plants during this plague, large tequila producers still favor agave farms that are at the greatest risk for future plagues. Valenzuela and Nebhan close their book commenting on the remarkable growth of tequila in general and premium tequila in particular and they express a hope for continuation of the tequila industry because of its significant economic benefit to people in the industry. However, their primary concern is that the reliance on mono-cropping and the cloning of blue agave puts the whole industry at risk for future distribution if a new pathogen wreaks havoc in the genetically uniform fields of Jalisco.

Valenzuela and Nebhan's book is a unique and important book for any tequila aficionado. Now that the book is over ten years old, its information is by no means revolutionary or completely novel, but that does not mean it is outdated. Valenzuela and Nebhan bring a scientific perspective to agave and tequila that is uncommon in most of the literature. Most other books on tequila are written by bartenders, drink writers and others in the alcohol or service industry. While other books contain information on the scientific aspects of agave cultivation and the potential dangers of mono-cropping and cloning, Valenzuela and Nebhan offer credible a solution to this problem. Their suggestion to reincorporate traditional cultivation practices are not born out of a Luddites nostalgia for the past but a scientific understanding of best practices that will promote the continued health of blue agave and its genetic resistance to new pathogens. This in the end will ensure that tequila will be able to be enjoyed for generations to come.