A Trip to the Past

In view of the uproar about Carolyn Walker-Diallo's swearing in - she used a Quran - I started thinking about the January 2013 swearing-in of Obama.  Remember it?  He botched the words, so took the oath again, in a private ceremony.

I wondered at that time about the book that was contained between the covers - never did get an explanation.

Does anyone reading this know what that book was?