«'O'Hara does a great job of covering both the old (late 1800s) and the new (1960–70) history of geology. Included are informative, but concise, biographies of all the major players in the nineteenth and twentieth centuries. The author shows very clearly how Wegner's continental drift - which was not originally accepted by the scientific community - came together with Harry Hess's seafloor spreading in the 1970s, and led to the 'Great Plate Tectonic Revolution' in the Earth Sciences. I really liked the chapter on isotopic dating, where the author clearly explains how geologists learned to use isotopes to date geologic events - no other book on the history of geology illustrates this so clearly. And another outstanding feature of the book is Chapter four, where the author shows how the geologic community used experimental results to better understand the origin of magmas.' Kent Condie, New Mexico Institute of Mining and Technology»

«'The nearly four-century existence of geology as a concept - 'the study of the Earth with its Furniture' as it was first put - has been mired in periods of uncertainty, revolution, speculation and controversy. Kieran D. O'Hara has tied it all up in a concise, neatly arranged and highly readable summary, essential to all who want to know more of the fascinating story of this most fundamental of sciences.' Simon Winchester, author of The Map That Changed the World»