These three excellent papers present the ground‐water conditions and problems or the San Joaquin Valley from three different points of view. Taken together they comprise a very good picture of the ground‐water resources of the Valley. As the water‐supply problems of the San Joaquin Valley are more acute in the portion of the Valley south of Chowchilla River it is natural that the authors devote more of their discussion to this portion. This should not cause us to lose sight of the fact that a large part of the best development in the Valley is in its northern part where nature has been more liberal in providing an adequate water