The pervading theme of the book is the struggle to green a brown land. The early settlers applied English farming methods developed in a green land of cool, moist summers. During the ensuing 200 years these methods had to be relearned in a brown land of long dry spells. The attempts to grapple with sustained aridity are explored within three themes: the destruction of the native grasslands and the struggle to regreen them with sown pastures, the development of cropping practices appropriate to a land of long dry summers, and the attempt to green the land by developing large irrigation schemes.