The categorization of the past into discrete, quantified named blocks of time is called periodization. This is a list of such named time periods as defined in various fields of study. Major categorization systems include cosmological (time periods in the origin and evolution of the universe), geological (time periods in the origin and evolution of earth), anthropological (time periods in the origin and evolution of humans) and historical (written history). These can be divided broadly into prehistorical (before history began to be recorded) and historical periods (when written records began to be kept). This book gives a comprehensive overview of the human, geological and cosmological time periods of the earths history. This book is designed to be a state of the art, superb academic reference work and provide an overview of the topic and give the reader a structured knowledge to familiarize yourself with the topic at the most affordable price possible. The accuracy and knowledge is of an international viewpoint as the edited articles represent the inputs of many knowledgeable individuals and some of the most current knowledge on the topic, based on the date of publication.