In the first part of this paper, the Concept of "Sustainable Agriculture" is presented and discussed. Then a holistic view of drylands is given, starting with the aridity definition, then the location of drylands around the world. Drylands climate, soils and population are also characterized. The second part of the paper gives the principles and fundamentals of "Sustainable Agricultural Management of Drylands" at the regional level and the farm level. The role of education and extension is presented, the relation between natural resources exploitation and aridity is discussed.