Book excerpt: This innovative survey of world history from earliest times to the present focuses on the role of four factors in the development of humankind: climate, communication and transportation technology, scientific advances, and the competence of political elites. Matossian moves chronologically through fifteen historic periods showing how one or more of the causative factors led to significant breakthroughs in human history. Shaping World History is based on original research and also draws widely from the literature on the history of science, technology, climate, agriculture, and historical epidemiology. This compelling analysis is presented in a personal style and includes reflections on how things work and why they are important.