As of October 2020, all physical formats of the titles published by Recorded Books
and its imprints in USA are produced by Blackstone Publishing. The credits for these books may include Recorded Books, one of its imprint or the paper/ebook publisher name in addition to the Blackstone Publishing name. This is also valid for books that are produced by Blackstone Publishing for other publishers (either just the physical audio formats or the audio downloadable ones as well).
Similar agreements had been completed with other publishers (the list on the official site includes Blackstone, Hachette, HarperCollins, Harlequin Audio, Penguin Random House, Brilliance, Scholastic, Bolinda, Recorded Books, HighBridge, Tantor, Naxos, Macmillan Audio, and Simon & Schuster).
As a result not all titles are listed in this publisher: See this list
for the combinations.
See also Blackstone Audio
and its combinations
At this time it is unclear if "Blackstone Audio" and "Blackstone Publishing" should be treated as one publisher.