body: I am writing Lovecraftian horror short fiction. I know I can use Lovecraft's material written 1923 and prior. However, I would love to use parts of the genealogy he noted in some of his letters. These letters, and others, were published in <https://en.wikipedia.org/wiki/Selected_Letters_of_H._P._Lovecraft_IV_(1932%E2%80%931934)> in 1976. The letters themselves were written from 1932-1934.
  
  
  Are these letters considered in the public domain, as unpublished works (by the author) written 88 years ago? If not, when would they enter the public domain?
  
  
  
title: Copyright status of an author's letters published posthumously?