Burchfield charts the enormous impact made by Lord Kelvin's application of thermodynamic laws to the question of the earth's age and the heated debate his ideas sparked among British Victorian physicists, astronomers, geologists, and biologists. "Anyone interested in geologic time, and that should include all geologists and a fair smattering of biologists, physicists and chemists, should make Burchfield's commendable and time-tested volume part of their personal library"-Brent Darymple, Quartely Review of Biology