In this 1974 book a practising scientist and gifted expositor sets forth an exciting point of view on the nature of science and how it works. Professor Ziman argues that the true goal of all scientific research is to contribute to the consensus of universally accepted knowledge. He explores the philosophical, psychological and sociological consequences of the principle, and explains how, in practice, the consensus is established and how the work of the individual scientist becomes a part of it. The intellectual form of scientific knowledge is determined by the need for the scientist to communicate his findings and to make them acceptable to others. Professor Ziman's essay, being written in plain English, and requiring only the slenderest knowledge of science, can (and should) be read by any educated person; as he says 'all genuine scientific procedures of thought and argument are essentially the same as those of everyday life'.