Tracking the U.S. election through book sales

As the U.S. election campaign ramps up to the November 6 vote, online retailer Amazon has been using a frequently updated "heat map" to track conservative-themed "Red" and left-leaning "Blue" political book sales throughout the country in the past month.

The company describes the map as a "novel way to follow the political conversation this election season," and not a scientific measure by any means.

amazon-heat-map.jpgAs of Wednesday morning, "Red" books accounted for 56 per cent of political book purchases through in the last 30 days, with "Blue" books making up the remaining 44 per cent.

When it comes to books written by the presidential candidates, incumbent President Barack Obama is selling many more books than Republican leader Mitt Romney -- 64 per cent compared to 36 per cent.

However, when looking at books written or co-authored by the vice-presidential candidates, the GOP's Paul Ryan crushes Democratic incumbent Joe Biden in head-to-head book sales -- 94 per cent to 6 per cent.

The top three "Blue books" as of Wednesday morning were: A People's History of the United States by Howard Zinn, The New Jim Crow by Michelle Alexander and Cornel West, and The New New Deal by Michael Grunwald.

The top three "Red books" as of Wednesday morning were: The Amateur by Edward Klein, Killing Lincoln: The Shocking Assassination That Changed America Forever by Bill O'Reilly, and Leading from Behind: The Reluctant President and the Advisors Who Decide for Him by Richard Miniter.