This came up the other day and someone emailed me off-list suggesting it wasn't true. Since we've never had a real discussion about it, I should explain:
17 U.S. Code § 203 - Termination of transfers and licenses granted by the author
(a) Conditions for Termination.—In the case of any work other than a work made for hire, the exclusive or nonexclusive grant of a transfer or license of copyright or of any right under a copyright, executed by the author on or after January 1, 1978, otherwise than by will, is subject to termination under the following conditions: ... (3) Termination of the grant may be effected at any time during a period of five years beginning at the end of thirty-five years from the date of execution of the grant; or, if the grant covers the right of publication of the work, the period begins at the end of thirty-five years from the date of publication of the work under the grant or at the end of forty years from the date of execution of the grant, whichever term ends earlier.
So, we still have 19 years, but, we're almost halfway there.