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..
Maud Gage Baum
Beginning in 1900, her husband's best-selling picture book, "" (first published in 1899), brought the family financial security that it had theretofore lacked. They began spending their summers at a cottage in Macatawa Park, Michigan. In November of that year, Frank transferred to Maud the literary rights of his most recent books, including "Father Goose" and "From Kansas to Fairyland" (later published as "The Wonderful Wizard of Oz"). By dint of Frank's literary successes, Maud and Frank were financially secure enough to tour Egypt and Europe for six months. Since Frank was frequently occupied with penning stories for his publishers, Maud was the one who wrote numerous letters home. These letters were later published in 1907 as "In Other Lands Than Ours" for friends and family. After Frank died, she authorized Ruth Plumly Thompson to write more Oz sequels and helped promote MGM's film "The Wizard of Oz" (1939). In 1953, she died at 91 years of age, surviving her husband by 34 years.