Errata lists in the early days of printed books, then, were themselves a sort of early comment section—the place where revisions were made and ideas were exchanged. They were “confessional spaces” and “emblems of a new culture of accuracy,” but errata lists were also a way of seeing books as a collaboration between reader and writer, rather than just the one-way broadcasting of a set of ideas.
Adam Smyth, an English literature fellow at the University of Oxford, said centuries ago, “errata lists became, paradoxically, markers of well-made books.” The made in “well-made” is a key word here. Mistakes can serve as reminders that books are made at all—the physicality of the process, the “connection between the book going wrong, momentarily, and a sense of the process of production being briefly revealed, or implied,” as Smyth put it in a recent paper about print in Early Modern England.
Here’s the errata list from Edmund Spenser’s “The Faerie Queen,” an epic poem from 1590:

Back in the medieval days, a scribe had different ways of fixing errors, from a knife to gently scrape the error off the page, to the strikethrough as seen in the redline of the Domesday book of 1086.

Errata also leads us down the rabbit hole of Marginalia. What annotations did people place in their texts? What do their markings tell us about how the book was read? Remember, back in the 19th century, Paper was expensive; and the process to make it even more so. So people shared what they had and didn’t have a lot of copies in a library, per se, to borrow.
To that end, check out what BOOK TRACES is doing, spearheaded by the University of Virginia, to discover and document handwritten inscriptions, marginallia, and other readerly markings in old library books.
Interested? Read more here:
Craig Silverman’s Poynter article from 2014 about Gawker’s rejection of the strikethrough correction.
Bryan C. Keene’s Getty article on Medieval Copyediting (fascinating) and where the featured image for this blog post comes from.
More on Book Traces, exploring the past through marginalia in library books via U. Conn Library
Featured image courtesy of Getty.edu “Detail from a Decorated Canceled Page in the Abbey Bible, about 1250–62. Ms. 107, fol. 96v” https://blogs.getty.edu/iris/medieval-copyediting/