The New York Times, September 8, 1900
The Wonderful Wizard of Oz received positive critical reviews upon release. In a September 1900 review, The New York Times praised the novel, writing that it would appeal to child readers and to younger children who could not read yet. The review also praised the illustrations for being a pleasant complement to the text.
During the first 50 years after The Wonderful Wizard of Oz's publication in 1900, it received little critical analysis from scholars of children's literature. According to Ruth Berman of Science Fiction Studies, the lists of suggested reading published for juvenile readers never contained Baum's work. The lack of interest stemmed from the scholars' misgivings about fantasy, as well as to their belief that lengthy series had little literary merit.
It has frequently come under fire over the years. In 1957, the director of Detroit's libraries banned The Wonderful Wizard of Oz for having "no value" for children of his day, for supporting "negativism", and for bringing children's minds to a "cowardly level". Professor Russel B. Nye of Michigan State University countered that "if the message of the Oz books—love, kindness, and unselfishness make the world a better place—seems of no value today", then maybe the time is ripe for "reassess[ing] a good many other things besides the Detroit library's approved list of children's books".
In 1986, seven Fundamentalist Christian families in Tennessee opposed the novel's inclusion in the public school syllabus and filed a lawsuit. They based their opposition to the novel on its depicting benevolent witches and promoting the belief that integral human attributes were "individually developed rather than God given". One parent said, "I do not want my children seduced into godless supernaturalism". Other reasons included the novel's teaching that females are equal to males and that animals are personified and can speak. The judge ruled that when the novel was being discussed in class, the parents were allowed to have their children leave the classroom.
Leonard Everett Fisher of The Horn Book Magazine wrote in 2000 that Oz has "a timeless message from a less complex era, and it continues to resonate". The challenge of valuing oneself during impending adversity has not, Fisher noted, lessened during the prior 100 years.
In a 2002 review, Bill Delaney of Salem Press praised Baum for giving children the opportunity to discover magic in the mundane things in their everyday lives. He further commended Baum for teaching "millions of children to love reading during their crucial formative years".
The Library of Congress has declared The Wonderful Wizard of Oz to be "America's greatest and best-loved homegrown fairytale", also naming it the first American fantasy for children and one of the most-read children's books.