Agricultural systems and methods for their study; The systems approach and agriculture; The system and the agricultural system; Classification of agricultural systems; Mathematical methods for the study of agricultural systems; Methodology of simulation; What is simulation? The process of simulation; Simulation of agricultural production systems; Simulation of plant cultivation systems; Simulation of production processes systems; New features in the technological development in agriculture; Modelling and simulation at the level of agricultural firms; Linear dynamic models for medium-term plans; Simulation of the entire farm; The modelling of national agricutural systems: the long-term development perspectives of the Hungarian food production; Various ways of modelling national agricultural systems; The system model of the centrally planned food and agriculture; The simulation model of the Hungarian food production; Perspectives in the long-term development of Hungarian food production as projected by HAM; International agricultural models: the agriculture of the CMEA in 2000; The structure of the international agricultural models; Major types of the international agricultural models; Limits and potentials in the development of CMEA agriculture: the use of an international model.