As the British Society for the History of Science's president during its fiftieth year, it gives me the greatest pleasure to introduce this anniversary issue of the Journal. For some readers there will be a special poignancy in recalling the vision and energy of the Society's founding fathers who, believing that the history of science had a strategic role to play both as a humanizing force and as an integral part of the culture of science, turned their belief into action. Many justifications have been and will continue to be given for the importance of our subject. Prominent among them when the Society was launched in 1947 was that the history of science would underpin claims for the inherent progressiveness and universality of scientific knowledge. In his presidential address, delivered in May 1948, the Society's first president, Charles Singer, also drew a parallel between the humanism of the Renaissance and a new humanism represented by the cultural possibilities of this history of science: both had had ‘small beginnings in a disturbed world’.