The confusing answer is maybe:
Many books published in the U.S. between 1923 and 1963 are actually in the public domain, since the author/publisher neglected to renew the item’s copyright protection, and such renewals were not automatic. It’s also relatively easy to determine if copyright on such an item was renewed or not.
A periodical published between 1923 and 1963, however, is a different story. Why? Because it’s not just the publisher of the periodical who can renew copyright: authors of articles in the periodical may have renewed copyright on their own individual contributions: