In 1936 a German chemist identified certain organic molecules in ancient rocks and oils as the fossil remains of chlorophyll, presumably from plants that had lived millions of years in the past. Many years later this insight was revisited and the term biomarker coined to describe fossil molecules whose molecular structures could reveal the presence of otherwise elusive organisms and processesand then, the hunt was on. Echoes of Life is the story of those molecules and how they illuminate the history of the earth and its life. It is also the story of how a few maverick organic chemists and geologists defied the dictates of their disciplines and, at a time when the natural sciences were fragmenting into ever-more-specialized sub-disciplines, reunited chemistry, biology and geology in a common endeavor.