As of Thursday evening, Sen. Elizabeth Warren's new memoir, A Fighting Chance, is the number two best-selling book on Amazon, trailing only Thomas Piketty's Capital In The Twenty-First Century. Michael Lewis' Flash Boys, which exposes the world of high-frequency traders, is number five. Both Capital and A Fighting Chance are also among Barnes & Noble's top five sellers. Rounding out Amazon's top five are John Green's YA hit The Fault In Our Stars and an illustrated Little Golden Book adaptation of Disney's "Frozen." Both books are more representative of typical Amazon best-sellers, which tend to include popular fiction and self-help titles.