There is a national index of rare books that only a handful of libraries have a copy of; you can get scans through ILL. https://en.wikipedia.org/wiki/National_

There is a national index of rare books that only a handful of libraries have a copy of; you can get scans through ILL. https://en.wikipedia.org/wiki/National_Union_Catalog https://en.wikipedia.org/wiki/National_Union_Catalog