First published in 1992, The Proterozoic Biosphere was the first major study of the paleobiology of the Proterozoic Earth. It is a multidisciplinary work dealing with the evolution of the Earth, the environment and life during the forty percent of Earth’s history that extends from the middle of the Precambrian eon (2500 Ma) to the beginning of the Paleozoic era (550 Ma). The book includes a vast amount of data on Proterozoic organisms and their analogs. Prepared by the Precambrian Paleobiology Research Group, a multidisciplinary consortium of forty-one scientists from eight countries, this monograph was a benchmark in the development of the science of the biochemistry and the organic chemistry of Proterozoic sediments. The study aimed to generate data and analyses based on the re-examination of previous studies and on newer investigations and to build towards the future by placing special emphasis on neglected aspects of paleobiologic study and unsolved problems in the field.