Copyright status of The Wizard of Oz and related works in the United States
"The Wonderful Wizard of Oz" was published in 1900, and was the first to enter the public domain in "1956". This allowed Reilly & Lee, the publisher of all the other Oz books (as well as Baum's other books) to issue their own edition of "The Wizard of Oz", which had previously been published by George M. Hill Company and later by the Bobbs Merill Company after Hill went bankrupt..
The Wizard of Venus
"The Wizard of Venus" was first published in the 1964 Burroughs collection "Tales of Three Planets" together with the unrelated tales "The Resurrection of Jimber-Jaw", "Beyond the Farthest Star" and "Tangor Returns". Afterwards it appeared in the collection "The Wizard of Venus" (Ace Books, August 1970). This also included the unrelated pirate adventure "Pirate Blood." A subsequent British edition (New English Library, 1975) omitted the unrelated story.