Scientists and peasants? Mexico and contraceptive pills? For most readers these are social groups and themes that have no connection, but in this book, they do. This is a fascinating account, based on archival research and oral interviews, of the changing relationship between chemists, pharmaceutical companies, politicians and Mexican peasants around the use of a wild yam known as barbasco (Dioscorea mexicana), from which progesterone can be synthesised. The plant was essential to the manufacture of the first oral contraceptives, among other drugs such as cortisone, during most of the Cold War years (1940s to 1970s). The dimension of the enterprise is illustrated by the following figures: by the late 1950s Mexico was producing nearly 90 per cent of the world's steroid hormones, and by 1960 more than 100,000 peasants were gathering the raw material used in the production of birth control pills (widely used in the United States and internationally in USAID's family planning programmes).

Jungle Laboratories depicts poor rural inhabitants of the south of Mexico, mainly from Oaxaca, initially linked to North American scientists and international pharmaceutical companies interested in the mass production of steroid hormones. Later, in the early 1970s, the Mexican government launched a campaign to ‘rescue’ barbasco pickers from greedy transnational pharmaceutical companies. The populist Mexican president Luis Echeverría, who ruled the country between 1970 and 1976, nationalised the exploitation of barbasco and created an ambitious state-subsidised company called Provimex (an abbreviation of the Spanish for Mexican Chemical Vegetable Products). It is important to note that President Echeverría was considered a leftist in comparison with previous administrations, redistributed millions of acres among the landless peasantry and introduced an aggressive family planning programme to reduce population growth, perceived at the time as one of the major challenges for the development of the country. After a few years of existence the state-run company could not overcome a number of technical and social problems (for example, during the mid-1970s barbasco lost ground to alternative synthetic materials) and ultimately failed as a business. The company was dissolved in the late 1980s as part of a neoliberal programme of reforms. Unfortunately, the author was unable to examine all the archives of this company.

At the beginning of the story peasants were guides and cutters and pickers of wild yam, working for foreign scientists and metropolitan companies and unaware of the high value of the plant for international markets. Later, peasants became conscious of the value of barbasco, and used their knowledge and resources to negotiate a share of the profits, lobbied or confronted the state demanding improvements in their living conditions, and made an effort to be recognised as citizens by the rest of the country. As a result, Mexican peasants linked to the barbasco trade experienced a transition in their self-image from uninformed gatherers to vocal leaders for social change in the impoverished countryside. Moreover, some of them participated directly in the international networks of science and industry. For example, some peasant leaders working for Provimex travelled to Germany to learn at the Schering laboratory how the yam was chemically transformed into steroids.

The book reveals the role played by crucial individuals such as the American scientist Russell Marker, a member of the Rockefeller Institute, who was one of the first researchers to study raw materials for synthetic steroid hormones in Mexico. Marker was also important because he was a pioneer of the steroid industry in Mexico (in the 1940s he created the Mexico-based company Syntex, which produced the oral contraceptive pill and a cheap supply of cortisone). In addition, the book analyses the contribution of the lesser-known Mexican chemist Luis Ernesto Miramontes, the co-discoverer of the chemical compound that led to the production of oral contraceptives (more precisely, he was the first researcher to synthesise the compound norethindrone, the basis for the first oral contraceptive, progestin), and a number of Oaxaca's local middlemen, union members and peasants – the new peasant ‘experts’ who exercise leadership in their communities.

Soto Laveaga has produced an important work on the political economy of barbasco that brings to the fore a little-known chapter in the creation of the contraceptive pill and analyses the way in which scientific issues go beyond metropolitan academic scientific communities and filter down to apparently remote pockets of rural societies engaged in the exportation of primary products. This splendid work suggests that social Latin American historians can make a significant contribution to understanding the recent political development of medicinal plants and human reproductive programmes. It is also a remarkable study because it inscribes scientific developments in the history of Mexico in the second half of the twentieth century, a period when many peasant demands – predominant shortly after the revolution and during the inter-war period – were apparently obliterated with the hegemony of modernising industrialist programmes directed by the state.