In this book, Cherry Lewis skilfully blends the history of gauging the age of the earth with a biography of Arthur Holmes, a British geologist who was a pioneer of geochronology. When it was deeply unfashionable to do so in the early twentieth century, he spent many years trying to prove the great antiquity of the earth, stating that it was 'perhaps a little indelicate to ask of our Mother Earth her age, but Science acknowledges no shame'. Both fascinating and touching, this book appeals to a broad readership of both geologists and science enthusiasts.