The World of Null-A

Grosset & Dunlap issued a 1950 hardcover reprint, also titled "The World of Ā" and carrying a Groff Conklin introduction; the G&D imprint on the spine and title page is the reprint tell, and copies are commonly mistaken for the S&S first because the S&S first has no edition statement to contrast against. Later Ace paperbacks retitled the book "The World of Null-A". No separate book-club issue is documented in the sources consulted.