Last week, we took a look at the sales of the movie-tie-in edition of Twelve Years a Slave in the run-up to the Academy Awards on March 2. The film based on Solomon Northup's 1853 memoir took home three Oscars on Sunday, including the big one—best picture. There's been some coverage of the book's jump on Amazon's bestseller list over the weekend, climbing over 300 spots on the overall chart.

But, drilling down to a niche category, 19th century U.S. history, we noticed various versions of the book, across formats, currently occupy the top six slots, with an e-book from HarperPerennial Classics at #1. In fact, editions of the 161 year-old title take thirteen of the top 20 spots in the category.