The phenomenal success of Star Wars action figures and related merchandise revolutionized the toy industry. The first trilogy of movies that appeared in the late 1970s and early 1980s fueled about $2 billion in sales of Star Wars-related toys, especially Kenner-made action figures. Since the late 1970s, American toy makers have put more of their business into the production of toys tied to successful movies, television series, comic books, and other popular entertainments. Some parents, child psychologists, teachers, and experts lament that the reliance on toys related to mass media, with their back stories, stock characters, and standard good versus evil plots, rob kids of opportunities to use their imaginations. Other child specialists point out, however, that kids do use their imaginations in creating their own stories about characters like Luke Skywalker and Darth Vader. Additionally, some suggest that in a child?s world where playmates may speak different languages and follow different cultural traditions, all children find common ground in Yoda and other action figures to share and to base play and friendships on.