When is a termination possible?
Copyright law includes a 'termination transfer right' after 35 years. The window of opportunity is open for only 5 years and advance notice must be sent to the publisher. Note that the publisher may be notified two years or more before the beginning of the 5-year window so that termination may be effective exactly 35 years after publication.
The Copyright Office website will have details about the date of publication of your piece and the date and registration number of the copyright. (Search the Public Catalog.)
To find the earliest and latest dates for notifying the publisher, fill in the dates and answer the questions on the website rightsback.org. The earliest and latest dates for notification and the earliest and latest dates for the termination to take effect will also be provided.