William Thomson, first Baron Kelvin (1824-1907), is best known for devising the Kelvin scale of absolute temperature and for his work on the first and second laws of thermodynamics, though throughout his 53-year career as a mathematical physicist and engineer at the University of Glasgow he investigated a wide range of scientific questions in areas ranging from geology to transatlantic telegraph cables. The extent of his work is revealed in the six volumes of his Mathematical and Physical Papers, published from 1882 until 1911, consisting of articles that appeared in scientific periodicals from 1841 onwards. Volume 5, published in 1911, includes articles from the period 1847-1908. Topics covered include thermodynamic and electrodynamic research, as well as some works on issues of geological physics such as the possible age of the sun's heat.