• William J. Duiker and Jackson J. Spielvogel.  The Essential World History: to 1400.  Thomson/Wadsworth,  2nd edition, 2005.
• Jared Diamond. Guns, Germs, and Steel: The Fates of Human Societies, Norton, 1997.
• David Christian. Maps of Time: An Introduction to Big History, University of California Press, 2004.