Jonathan Franzen

Oprah is on a farewell tour of sorts, what with The Oprah Winfrey Show ending its 25 year run in 2011. But those who were saddened by the thought that Jonathan Franzen's No. 1 bestseller Freedom would be her final pick for her wildly popular Book Club can breathe easier: You get at least one more.

From history and economics to crime novels and biographies, whatever book the president touches -- and talks about -- turns into sales gold. Americans are very clearly interested in whatever the president is reading, and they're buying accordingly.