Farming structures worldwide, but particularly in transition economies, are extremely diverse. In transition countries, they are often dualistic in the sense that small and large farms coexist. Each type of operation is faced with its own specific challenges. Therefore one of the main goals of this research domain is to contribute to a better theoretical understanding of structural change in agriculture. Considering structural change as a complex dynamic and evolutionary process, the theories of complex adaptive systems and systems theory provide a conceptual basis. On a more applied level, a key topic is the increasing capital and knowledge intensity of modern farming. Further key topics address large-scale farms (agro holdings) and the role of semi-subsistence operations.