William Thomson, Baron Kelvin (1824-1907), was educated at Glasgow and Cambridge. While only in his twenties, he was awarded the University of Glasgow's chair in natural philosophy, which he was to hold for over fifty years. He is best known through the Kelvin, the unit of measurement of temperature named after him in consequence of his development of an absolute scale of temperature. These volumes collect together Kelvin's lectures for a wider audience. In a convivial but never condescending style, he outlines a range of scientific subjects to audiences of his fellow scientists. The range of topics covered reflects Kelvin's broad interests and his stature as one of the most eminent of Victorian scientists. Volume 2 is mainly concerned with geology and was actually published last, in 1894. It includes additional lectures given between 1866 and 1893 that were not included in the other two volumes.