The Hardy Boys have evolved in various ways since their first appearance in 1927. Beginning in 1959, the books were extensively revised, largely to eliminate racist stereotypes. The books were also written in a simpler style in an attempt to compete with television. The original Hardy Boys Mystery Stories series ended in 2005.
Through all these changes, the characters have remained popular. The books sell more than a million copies a year. Several additional volumes are published annually, and the boys' adventures have been translated into more than 25 languages. The Hardy Boys have been featured in computer games and five television shows and used to promote merchandise such as lunchboxes and jeans. Critics have offered many explanations for the characters' longevity, suggesting variously that the Hardy Boys embody simple wish-fulfillment, American ideals of masculinity, a paradoxically powerful but inept father, and the possibility of the triumph of good over evil.