Would recommend this link for Latin American specialized catalogues -
https://classiclatinamerica.com/sou...-catalogues/Re your question, yes, much should be in the public domain - as in titles available through Project Gutenburg. But - someone has to go the effort of scanning/hosting it, so you often see public domain stuff available only at paid sites.
That book in particular I saw is also available at Abebooks.com, not just at scribd.