Stefan Milne writes: “Seattle Public Library is the only US library system that makes its anonymized, granular checkout data public. The hitch is that the library’s data set contains nearly 50 million rows. To track trends in the catalog over the last 20 years, University of Washington researchers analyzed the checkout data of the 93 authors included in the post-1945 volume of The Norton Anthology of American Literature, which is instrumental in standardizing the books and writers we’ve deemed culturally important.”