|L to R: Mr. and Mrs. Arthur Miller|
This has prompted me to look up what the guidelines are for giving manuscripts to libraries.
The two greatest libraries in the United States are the NY Public Library and the Library of Congress.
Here is what the NY Public Library – the library with by far the largest number of visitors – has to say: https://www.nypl.org/help/about-nypl/legal-notices/policy-gifts-materials.
Here is what the Library of Congress says: https://www.loc.gov/acq/donatex.html
These are two of the five greatest (largest) libraries of the world, the others being the Bodleian (Oxford), the British Library (London) and the Bibliothèque Nationale de France (Paris). This is not to put down the many smaller libraries that may be tops in their specialized areas.
For a charitable deduction from taxable U.S. income, my understanding is that gifts to foreign libraries would have to be through a charity based in the United States.