What is the theme in The House of Morgan by Ron Chernow?

The underlying theme of the book is power. The House of Morgan is, at one time, more powerful than most governments. J.P. Morgan is the most powerful man in the country. Presidents and heads of state come to him for assistance. The Morgans have enough power to get their own people released from Nazi camps. They have enough power to put together loans that save the pound and dollar from collapse under the gold standard. The House of Morgan is able to prevent many stock market crises.