The pressure to develop new agricultural technologies will be roughly proportional to the rate of depletion of natural resources employed in agriculture. Of these resources, land, water and gentic resources are critical. The development of agriculture is associated with a scientific and technological establishment, of remarkable capability ; responding rapidly to many problems encountered by the agricultural production. These advantages are also coupled with constraints. Agricultural systems are concerned with the efficient conversion of resources into products that are wanted by the producer or someone else who is prepared to pay for them. They are based on biological processes, but they are operated by the people for a multiplicity of purposes. Study of agricultural systems is aimed at helping in the operation of systems, their repair or their improvement. The future concerns of agriculture will center on (1) increasing and safeguarding the supplies of productive inputs to agriculture, (2) improving the efficiency with which these inputs are used in food production, (3) developing new sources of basic food materials, and (4) coping with the external costs that tend to appear in intensive, mechanized agriculture.