Our new book, "Loving and Hating Mathematics," is about the emotional, social and political aspects of mathematical life. A major chapter tells of mathematical communities, such as Gottingen in the early 20th century, Bourbaki in Paris, and the Courant Institute in New York. The creation of such a productive community often depends on the leadership and vision of a vital, charismatic figure How the community continues and endures depends on how its members internalize and develop that vision.