The third anthology was started but, controversially, failed to be published and became something of a legend in science fiction as the genre's most famous unpublished book.

British author Christopher Priest, whose story "An Infinite Summer" had been commissioned for TLDV in 1974 and withdrawn after four months without any response, wrote a lengthy critique of Ellison's failure to complete the project.

On November 13, 2020, the Ellison estate's executor J. Michael Straczynski announced that he would oversee the project to publish the book.

The book was advertised as containing "one last, significant work by Harlan which has never been published" which "ties directly into the reason why The Last Dangerous Visions has taken so long to come to light," although in practice this turned out to be an essay by Straczynski describing Ellison’s battle with bipolar disorder.

The contents of The Last Dangerous Visions were announced on several occasions, beginning in the January 1973 issue #7 of the semiprozine Alien Critic.

It was announced in the April 1979 issue of the Locus magazine that the anthology had been sold to Berkley Books, which planned to publish the 645,000 words of fiction in three volumes.

1” by Stephen Robinett and “The Size of the Problem” by Howard Fast, were presumably accepted by Ellison, as the authors died before Straczynski took over as editor.