?Smallholder farming plays a central role for the livelihood security of rural families in most low- to middle income countries. Beyond that it contributes to sustain important ecological functions and services. Yet, world-wide, increasing economic pressure threatens its viability, while young and capable labour force is attracted away to urban centres. In the Mexican state of Yucatán - where foremost indigenous Mayan people are practicing traditional farming under adverse natural conditions, using a broad variety of agro-biodiversity - these predominant trends can be observed like in a burning lens. Farming is more and more just performed for subsistence while cash for daily expenses is obtained from other sources. Aware of the sector’s benefits for society, Mexican policy makers recently put its services regarding food and livelihood security, agro-biodiversity, and maintenance of cultural heritage high on the agenda. Starting from that baseline, research teams affiliated to the University of Kassel and the Universidad Autónoma de Yucatán (UADY) conducted several interrelated research projects. All investigations are grounded in field work, including intensive interviews among local people and experts. The results are assembled in this volume.