Jeffrey S. Ankrom, an ALTA member and copyright attorney, passed us this excellent, useful link to a site on the Catalog of Copyright Entries. I especially recommend this section on how to determine if a copyright has been renewed.
Ankrom sent us a detailed "short version" of his process in figuring out the copyright status of All Quiet on the Western Front.
International copyright is very confusing. At least this CCE might give a starting point to some people!