Theologian Karen Armstrong's book forms the basis for this documentary. Looking at the way that humans have perceived the idea of a supreme being throughout history, A HISTORY OF GOD gathers interviews with representative's of several different religions to discuss the role that god plays in their lives. Discussing religious practices from various points in history, the program considers the many ways that the idea of a god situates itself in different cultures and communities. Religious scholars also offer their opinions on how various religions such as Christianity, Islam, and Judaism have affected and shaped one another.