Hermann von Helmholtz was a 19th-century pioneer of physiology and physics in Europe who was concerned with the implications of science for philosophy and culture. From the 1850s to the 1890s, he delivered over two dozen lectures, seeking to educate the public and to enlighten the leaders of European society and governments about the potential benefits of science and technology to a developing modern society. This text presents 15 of these lectures, which reflect the wide range of topics discussed by Helmholtz. Among the subjects covered are: the origins of the planetary system; the relation of natural science to science in general; the aims and progress of the physical sciences; the problems of perception; and academic freedom in German universities. This collection also includes Helmholtz's lectures on the relation of optics to painting and the physiological causes of harmony in music, which provide insight into the relations between science and aesthetics.