The Great Australian Artesian Basin within South Australia is discussed. Now restricted limits based on the hydraulic continuity of the main aquifer are suggested, and the occurrence and extent of suspended and subsidiary associated basins is outlined. The geology as related to hydrology and as evidenced particularly from bore log information is also discussed. This includes hard rock Precambrian basement, Permian, Blythesdale, Cretaceous, and also Tertiary Recent sediments. Special attention is given to the general hydrology, in quality and quantity of waters available, their intakes, natural outlets, and their chemistry. The urgent need for reliable levels, selective flow and pressure tests, and proper regulated control of all flowing bores is emphasied. Evidence is submitted of the dilapidated condition of many bore heads and drains.