But our current array of strategies may not necessarily reveal all the things we want to find. This will be obvious to historians, who work extensively with unpublished material. But it’s true even for printed books: works of poetry or fiction published before 1960, for instance, are often not tagged as “poetry” or “fiction.”

Visualization strategies themselves are a topic that could deserve a whole separate discussion.

Tim Kadlec, for example, is an excellent writer on the topic of performance. His personal site is a model of parsimony. He is full of wisdom on the topic of reducing bloat. But the slides from his recent talk on performance are only available as a 9 megabyte web page, or a 14 megabyte PDF.

That's almost 100 KB more than the full text of The Master and Margarita, Bulgakov’s funny and enigmatic novel about the Devil visiting Moscow with his retinue (complete with a giant cat!) during the Great Purge of 1937, intercut with an odd vision of the life of Pontius Pilate, Jesus Christ, and the devoted but unreliable apostle Matthew. For a single tweet.

By focusing on books that librarians have chosen to continue to make available to readers, OCLC was able to create a list of widely read novels that includes both classic texts and more recent, popular works by living authors.

We can use a similar approach to look at the nationalities of authors whose works are represented on the list. Focusing on the AUTHOR_NATIONALITY column, we can count how many times each country code appears, and see that over 80% of the novels were written by authors from the U.S. or the U.K.