NB: A free downloadable PDF of this text is available at a link at the bottom of this post.
Elli and I have discussed getting it translated to Greek too, but so far have not made much progress. We contacted the University of Minnesota press about it and It remains in copyright for another decade or two.
-A post from Cassius in 2019
2050. It remains in copyright until 2050.
I didn't know Cassius and Elli had taken that step, but I was curious about it myself, so I verified it with a search of the online records of the copyright office.
Here's how it works. In 1954, when the book was published, the term of copyright was 28 years from the date of publication, renewable for an additional 28 years. Both the original copyright notice and the renewal had to be registered with the Copyright Office. This would have given a maximum copyright life of 56 years, which would have ended in 2011.
But in 1976, and again in 1998, the rules changed. In order to deal with existing copyright protections, the following measure was introduced: for a work published in 1954 (to stick to the matter at hand), the work would remain in copyright for 95 years, if and only if the copyright claimant had registered both (1.) the original notice at the time of publication, and (2.) the renewal notice at 28 years (1981). I have unfortunately been able to verify that both notices are on record.
Dewitt is listed as the copyright claimant. As he died in 1958, and his Classicist son died in
1981 [edit: 1966], it is not immediately clear who filed the renewal notice. His grandchildren? The University of Minnesota press?
I have more reading to do.