"þ" ("Th") runes. The additional illustrations proved so appealing that George Allen & Unwin adopted the colour plates as well for their second printing, with exception of Bilbo Woke Up with the Early Sun in His Eyes. Different editions have been illustrated in diverse ways. Many follow the original scheme at least loosely, but many others are illustrated by other artists, especially the many translated editions. Some cheaper editions, particularly paperback, are not illustrated except with the maps. "The Children's Book Club" edition of 1942 includes the black-and-white pictures but no maps, an anomaly. Tolkien's use of runes, both as decorative devices and as magical signs within the story, has been cited as a major cause for the popularization of runes within "New Age" and esoteric literature, stemming from Tolkien's popularity with the elements of counter-culture in the 1970s. Genre The Hobbit takes cues from narrative models of children's literature, as shown by its omniscient narrator and characters that young children can relate to, such as the small, food-obsessed, and morally ambiguous Bilbo. The text emphasizes the relationship between time and narrative progress and it openly distinguishes "safe" from "dangerous" in its geography. Both are key elements of works intended for children, as is the "home-away-home" (or there and back again) plot structure typical of the Bildungsroman. While Tolkien later claimed to dislike the aspect of the narrative voice addressing the reader directly, the narrative voice contributes significantly to the success of the novel. Emer O'Sullivan, in her Comparative Children's Literature, notes The Hobbit as one of a handful of children's books that have been accepted into mainstream literature, alongside Jostein Gaarder's Sophie's World (1991) and J. K. Rowling's Harry Potter series (1997–2007). Tolkien intended The Hobbit as a "fairy-story" and wrote it in a tone suited to addressing children although he said later that the book was not specifically written for children but had rather been created out of his interest in mythology and legend. Many of the initial reviews refer to the work as a fairy story. However, according to Jack Zipes writing in The Oxford Companion to Fairy Tales, Bilbo is an atypical character for a fairy tale. The work is much longer than Tolkien's ideal proposed in his essay On Fairy-Stories. Many fairy tale motifs, such as the repetition of similar events seen in the dwarves' arrival at Bilbo's and Beorn's homes, and folklore themes, such