Comment by acabal

As Robin mentioned the typical style is "fine art oil painting", with some wiggle room allowed for exceptionally difficult cases (like Asian-themed books, as there just wasn't much fine art on that subject pre-1930).

We also require that the art have some kind of connection to the book itself, so it's not just some random fine art. Sometimes the connection is a little fuzzy, but we do the best we can given that art must be pre-1930 and also must have been previously published.

(My personal favorite artwork selection of the books I worked on is The Communist Manifesto[1]. That painting was actually made specifically for a different book by Willa Cather[2], but I thought the peasant laborer, holding a sickle in one hand, with a faraway look in her eyes as the red sun rises behind her was just too good to pass up for Marx!)

1920ish was when it started becoming much more common for books to have illustrated dust jackets, so now that more books from that era and onwards are entering the public domain, we opt to use the first edition dust jacket if it's in the appropriate style. Fortunately for us, that era also happens to be the so-called Golden Age of Illustration so it's not hard finding beautiful art to use!

[1] https://standardebooks.org/ebooks/karl-marx_friedrich-engels...

[2] https://standardebooks.org/ebooks/willa-cather/the-song-of-t...