Science today is confronted by new and difficult social and ethical problems, to which the inherited systems of sociology and philosophy of science can offer no adequate solution. The problems have arisen from the transformation of the 'academic science' of the pre-war period into the 'industrialized science' of the present. In addition to the well-known difficulties over finance, recruitment, policy and morale, there are the pathological phenomena described as 'shoddy', 'entrepreneurial' 'reckless' and 'dirty' science, and runaway technology. \nTraditional theories of science, based on the assumption that the results of scientific research must be essentially good and true, are now widely recognized as obsolete. In this study the author offers a new interpretation: he analyses the work of science as the creation and investigation of problems, and demonstrates the role of choice and value-judgement, and the inevitability of error, in scientific research. The achievement of scientific knowledge is then seen as the outcome of a lengthy social process. In subsequent chapters it is shown how this analysis can bring new understanding to the technical and practical problems confronting science in the modern world and help us guard against the special dangers to which immature fields are exposed. The conclusions are not sceptical or nihilistic, but maintain that the continued health and vitality of science requires leadership of the highest order. The main growth-point for a conception of science appropriate to its future tasks and welfare is identified as 'critical science', devoted to the protection of the human and natural environment.